Joe Biden's transition team is warning that it may take "legal action" if the General Services Administration fails to make an official determination that Biden has won the election.

Driving the news: GSA Administrator Emily Murphy, a Trump political appointee, has not made the declaration — a so-called "ascertainment" — that would allow officials from Biden’s agency review teams access to the information they need in order to get to work.

1. Politics: Biden unveils coronavirus task force — Trump adviser leading election legal fight tests positive.
2. Health: Pfizer says its vaccine is more than 90% effective — U.S. coronavirus cases top 10 million.
3. States: 23 states set single-day coronavirus case records last week.
4. Business: Stock market roars higher after Pfizer vaccine news — The jobs recovery remains far from complete.
5. Sports: How the pandemic helped fuel 2020's golf boom.
6. 🎧Podcast: Pfizer CEO says he would've released vaccine data before election if possible.

Governments around the world are preparing to work with President-elect Biden — but they still have to navigate what could be a bumpy final 10 weeks of President Trump.

Split screen: Around the time Biden was holding his first call as president-elect with a foreign leader, Canadian Prime Minister Justin Trudeau, Trump was firing his secretary of defense, Mark Esper.

Armenian Prime Minister Nikol Pashinyan surprised his country and the world tonight by announcing that he had agreed to end the war in Nagorno-Karabakh on terms that were “unbelievably painful for me personally and for our people.”

Why it matters: The announcement followed confirmation that Azerbaijan had taken a critical town in the breakaway region, which is majority ethnic Armenian but lies within neighboring Azerbaijan.

Attorney General Bill Barr has authorized U.S. attorneys to conduct investigations into alleged voter fraud if there are "clear and apparently-credible allegations of irregularities" that could change the outcome of a federal election in a particular state, AP first reported and Axios can confirm.

Why it matters: President Trump has refused to concede the election to President-elect Joe Biden, alleging a conspiracy of widespread voting fraud and corruption by Democratic election officials. He has thus far not provided specific evidence for his claims, which have been shot down by both Democratic and Republican secretaries of state.

Sens. David Perdue and Kelly Loeffler (R) on Monday called on Georgia Secretary of State Brad Raffensperger, a Republican, to resign over what they said was his failure to deliver "honest and transparent elections."

Why it matters: Raffensperger, who dismissed the senators' demand, and Georgia Lt. Gov. Geoff Duncan (R) have said there is no credible evidence of systemic voter fraud in the state. President Trump has made baseless and unfounded claims that Democrats stole this year's election from him through widespread voter fraud and mail-in ballots.

The Dow closed up 2.9%, or 835 points, after Pfizer announced promising, though early, findings about the effectiveness of its coronavirus vaccine. The S&P 500 finished up 1.2%.

The state of play: The vaccine progress is fueling market optimism about a possible return to normal, as the coronavirus pandemic and social-distancing restrictions have held back the U.S. economy.

Rep. Tony Cárdenas (D-Calif.) is running for chair of the Democratic Congressional Campaign Committee (DCCC), as Democrats look for new leadership after failing to expand their House majority in last week's election, according to a source familiar.

Why it matters: Cardenas' consideration for this leadership post reflects a recognition among Democrats that they need to shore up their support with Hispanic voters and better understand the nuances of the Latino community to improve their electoral prospects.

Senate Majority Leader Mitch McConnell (R-Ky.) celebrated Republicans' congressional victories and defended President Trump's refusal to concede to Joe Biden, saying on the Senate floor Monday that Trump has "every right to look into allegations and request recounts."

The state of play: As of Monday afternoon, only four Republican senators — Sens. Lisa Murkowski (Alaska), Mitt Romney (Utah), Susan Collins (Maine) and Ben Sasse (Neb.) — had congratulated Biden on his projected victory.

Christopher Miller, director of the National Counterterrorism Center, will replace Mark Esper as acting secretary of Defense, President Trump tweeted on Monday.

Why it matters: Trump has clashed with Esper over a number of issues since the summer, and he was expected to be one of the first Cabinet secretaries to be removed after the election.

Pfizer on Monday announced that its COVID-19 vaccine has proven effective in over 90% of previously uninfected people, and added that it could have 50 million doses available by year-end.

Axios Re:Cap talks to Pfizer CEO Albert Bourla about vaccine data, distribution, politics, and how he reacted upon receiving the news.

The U.S. surpassed 10 million confirmed COVID-19 cases on Monday, according to Johns Hopkins data.

Why it matters: The U.S. has reported over 100,000 new coronavirus cases every day since last Wednesday, when it first passed the threshold, per the COVID Tracking Project.

President Trump has already told advisers he's thinking about running for president again in 2024, two sources familiar with the conversations tell Axios.

Why it matters: This is the clearest indication yet that Trump understands he has lost the 2020 election to Joe Biden — even as the president continues to falsely insist that he is the true winner, that there has been election fraud and that his team will fight to the end in the courts.

Housing and Urban Development Secretary Ben Carson tested positive for COVID-19, ABC News first reported on Monday.

Why it matters: Carson is the latest in a string of White House officials to contract the virus — days after Chief of Staff Mark Meadows also tested positive. Like Meadows, Carson attended the White House’s largely mask-free election night party last week alongside a group of other top officials in President Trump's Cabinet.

Pharmaceutical giant Pfizer announced Monday that its coronavirus vaccine trial was effective in preventing COVID-19 infections in 90% of previously uninfected people and did not produce any serious safety concerns.

Why it matters: Should the results bear out, it would potentially a huge breakthrough in the fight against the coronavirus pandemic.

With the Masters' first-ever November start just three days away, it's a great time to look back on 2020's golf boom.

Why it matters: Golf was a physical and mental safe haven for millions of Americans with cabin fever this year, and even moderate retention of the sport's newcomers could help buoy an entire industry for years to come.

Central banks already have started priming their collective money printers and in the coming months are poised to crank them up to 11, buying up more bonds and delivering more liquidity to markets.

Why it matters: The recent rally in equities now has more backing from central banks.

23 states set new highs last week for coronavirus infections recorded in a single day, according to the COVID Tracking Project (CTP) and state health departments. 15 states surpassed records from the previous week.

Why it matters: More states across the country are handling record-high caseloads than this summer.

GOP leaders and confidants of President Trump tell Axios his legal fight to overturn President-elect Joe Biden’s victory — which they admit is likely doomed — could last a month or more, possibly pushing the 2020 political wars toward Christmastime.

Why it matters: Most top Republicans have followed Trump’s orders not to accept the Biden victory, and to allow all legal options to be exhausted. That could mean weeks of drama — and, more importantly, distractions from the vital work of transitioning government for a change of power.

Joe Biden's transformation into president-elect Saturday kicks off a new era for tech, giving an industry that's found itself increasingly at odds with government the chance for a reset.

The big picture: Biden's ascent could see the restoration of some tech-friendly Obama-era policies but is unlikely to end the bipartisan techlash that grew during Trump's term.

Four years later, it’s still easy to hate on the polls. Even if they called the presidential race "right" this time, the national polls vastly underestimated support for President Trump once again, leading to a major industry soul searching about how to fix some fundamental problems.

Why it matters: Without data to provide a beacon for elections, there isn’t much else to go on.

Big tech has been the biggest corporate winner of the Trump presidency, according to an Axios analysis of public-company corporate financials.

Why it matters: The tech giants have spent the past four years facing increased scrutiny from Washington, and Google has even been hit by an antitrust lawsuit. But Google parent Alphabet has seen its profits soar by $12 billion per year since Trump's surprise election in November 2016.

The Supreme Court will hear oral arguments Tuesday over the future of the Affordable Care Act — the third time in eight years the ACA has been on the brink of life or death at the high court.

The big picture: For now, the smart money says that the court is likely to strike down what remains of the law’s individual mandate, but is unlikely to go along with the argument — advanced by both red states and the Trump administration — that the whole law has to fall along with it.

Climate change got more attention this election cycle than ever, but the (political) science is mixed on whether it helped or hurt candidates who ran on it.

Driving the news: Joe Biden campaigned on the topic more than any other presidential nominee, which climate activists say is a victory. But his wins in battleground states may have come in spite of it, not because of it, political observers say.

Tropical Storm Eta was unleashing strong winds, heavy rains and "dangerous storm surge" over parts of South Florida and the Florida Keys early Monday after making landfall in the state, per the National Hurricane Center.

The state of play: Hurricane warnings were in effect for the Florida Keys and for the state's coast, from Golden Beach to Bonita Beach, as the storm was packing sustained winds of near 65 mph with higher gusts.

After Joe Biden whiffed with Hispanic voters in some states, Democrats are urging the president-elect to nominate several Latinos to high-profile Cabinet positions.

Among those in contention: California Attorney General Xavier Becerra for Homeland Security, New Mexico Gov. Michelle Lujan Grisham for Health and Human Services, and Rep. Filemon Vela for Commerce or Transportation.