I mean, he's been money laundering for years before becoming the president, that could catch up with him. Then there's the money laundering that he almost certainly did with campaign funds. Emoluments violations, I don't know what the sentencing for that would be but it is a crime. Perjury, bribery, both things that he's definitely done in the recent past. I'm not saying that any of this will put him in jail, but he has committed a lot of crimes.

I should add, if the United States had any kind of functioning justice system at all, he would be in jail for hiding facts about the coronavirus. It might not technically be illegal, but it sure as shit was a crime.