It is technically banned by law, but there's no executive will to follow through on it anymore.
Basically, Trump started the ball rolling on the tiktok ban back during his first term, and it took congress the entire Biden term to pass a law that said "It's not ok for a FOREIGN owned company to collect and use American user data," but if they divest and let an American company take a controlling share then it's somehow OK. When he realized that he could curry favor with the young user base by reversing his position, Trump tweeted support for "saving tiktok" the night before the ban went into effect. Tiktok was already shutting itself down, sending its users into a panic that led many to join RedNote, a much more blatantly Chinese owned platform. It was "down" for about half a day before restoring service, thanking Trump for promising to not enforce his country's laws.
It doesn't mention the campaign contributions that may have helped sway Trump's position, but here's a full timeline courtesy of
The US TikTok ban – a full timeline
ironically, the anti "Chinese communist" zeal for banning TikTok pushed users to flock to RedNote, but that's not quite an accurate translation for the Chinese name of the app: 小红书, literally "little red book."
For those who are unfamiliar,
Shadow chancellor John McDonnell threw a copy of Mao's Little Red Book at George Osborne. What exactly is this tome?
www.bbc.com