The Trump administration is using private data to monitor immigration and the border, thanks to a massive database of cell phone records it purchased from private vendors.

Why it matters: Experts are concerned about the scale and use of the data, even if it appears to be on firm legal footing, the WSJ reports.

• "This is a classic situation where creeping commercial surveillance in the private sector is now bleeding directly over into government," said Alan Butler, general counsel of the Electronic Privacy Information Center, to the Journal.

Between the lines: The government is quickly putting this data to use alongside its own increased collection.

• ICE "has used the data to help identify immigrants who were later arrested."
• The border patrol "uses the information to look for cellphone activity in unusual places, such as remote stretches of desert that straddle the Mexican border."
• The government is collecting some migrants’ DNA at the border and fingerprinting teenagers.
• “These are the kinds of tools that will help ICE become more surgical over time, I just don’t trust that under this administration it will be used appropriately,” former acting ICE director John Sandweg told Axios' Stef Kight.

The big picture: In the U.S., the government seems to be leaning ever more into its ability to weaponize big data, reports Axios tech editor Kyle Daly.

• This is part of an ongoing trend where the U.S. government simultaneously tries to rein in how major tech companies use personal data while government agencies seek to harness those troves of data, per Axios' Sara Fischer and Scott Rosenberg.
• China and other authoritarian countries already use vast troves of data on their own citizens to stifle dissent and political opposition.

The bottom line: This adds to concerns about the tech industry's model of amassing hoards of data and assuring people it is fine because it gets anonymized.

1. The U.S. economy added 225,000 jobs in January, far above economists’ expectations of 161,000. Go deeper.
2. Antarctica just hit its warmest temperature in recorded history at 65°F. Go deeper.
3. President Trump's former Navy secretary endorsed Mike Bloomberg. Go deeper.
4. Activist investor Elliott Management acquired a roughly $2.5 billion stake in SoftBank Group, saying the market "significantly undervalues" the Japanese group's assets. Go deeper.
5. Women run the law journals at the 16 top schools in the U.S. for the first time in history, WashPost reports.

The XFL kicks off this weekend and gambling will be far more on public display.

• The big picture: The revived league owned by wrestling impresario Vince McMahon will appeal to fans accustomed to betting on professional or college football — and who otherwise would have nothing to bet on for months, the AP reports.

Between the lines: The XFL will allow its broadcasters to openly talk about betting lines, and they will be shown on-screen during telecasts, Axios' Kendall Baker notes.

• On the radio, the league has partnered with VSiN (Vegas Stats & Information Network) and iHeartRadio to create audio "BetCasts," which will cover live games through a wagering lens.