It was in April last year, the Senate passed a bill that deemed TikTok a threat to national security as its data scraping methods were found to be predatory and a risk to the American people.

The Senate gave ByteDance, the owner of TikTok, an ultimatum: either sell the popular app to a US government-approved entity and remain in the country or face a sweeping ban across both Android and iOS app marketplaces. ByteDance was given 270 to decide what it wants to do, and now, as we are approaching the deadline of January 19, the Biden administration has somewhat backpedaled on its decision, with a White House official speaking to ABC News and saying, "Our position on this has been clear: TikTok should continue to operate under American ownership."
Adding, "Given the timing of when it goes into effect over a holiday weekend a day before inauguration, it will be up to the next administration to implement." Notably, during Trump's first presidency, the former and now soon-to-be president called for the ban of TikTok, but recently, Trump has changed his tune, saying he will try and keep TikTok available in the US. However, neither Trump nor his administration has outlined a plan for exactly how that will happen.
Furthermore, national security advisor Mike Waltz said on Thursday to Fox News that under the federal law that bans TikTok extensions may be granted as long as there is a viable deal still on the table. Additionally, President Biden is able to award a 90 day extension if he is able to see progress toward a sale, but it appears ByteDance isn't taking that route and instead is choosing to fight the decision by the Senate rather than find a US-based buyer.
Read more: TikTok ban in US stands firm as court officially denies pause for January deadline