Harris unveils first major ad buy since Biden stepped aside

Driving the news: The Harris campaign also unveiled its first ad, titled "Fearless."

• The new ad highlights the vice president's experience as a prosecutor and attorney general of California — and criticizes Trump, with Harris accusing him of wanting "to take our country backward."
• "We believe in a future where every person has the opportunity not just to get by, but to get ahead. Where every senior can retire with dignity," Harris says in the ad.

Zoom in: The ad will air on local and national broadcast, cable, streaming, and social channels, the campaign said.

• The ad will run during high-profile events, the campaign said, including during the Paris Olympics and television shows like The Bachelorette.

What they're saying: "[Harris is] uniquely suited to take on Donald Trump, a convicted felon who has spent his entire life ripping off working people, tearing away our rights, and fighting for himself," Harris for President Campaign Chair Jen O'Malley Dillon said in a statement.

• "This $50 million paid media campaign, bolstered by our record-setting fundraising haul and a groundswell of grassroots enthusiasm, is one crucial way we will reach and make our case to the voters who will decide this election."

The other side: Trump's campaign is also spending about $12 million this week on ads to run in the major swing states until Aug. 12.

• The ads, which hit Harris on immigration, are the former president's first major ad buy since the vice president emerged as the presumptive Democratic nominee.

Go deeper: Kamala Harris' new challenge: translating momentum into votes