Nixon resigned and admitted guilt, with the guarantee of a pardon. If you've followed the news the last months, it's widely known T#### queried everybody with insight whether it's possible to pardon without that, and no one could find a reason for it to work. That would legally give a person one of those Bond licenses to kill or do anything they like, forever.
The problem that Trump has is that even if he were to be pardoned by Biden, it wouldn't help him much. This is because a lot of the investigations are state investigations, not federal. As a result, a pardon from the president wouldn't do a thing. He'd have to get pardons from all of those state governors. That's not going to happen, especially after the way he acted about losing the election and accusing all of these state governments of corruption. I mean, sure, they're corrupt alright but not about this and they're going to laugh in his face if/when he asks for a state pardon. I think that New York State is the farthest along in their criminal investigations of him.