Biden and Pence cooperated with the request from the FBI.
Trump did not. He then moved (multiple times) and destroyed evidence. Pence and Biden did not do that. While I disagree with VPOTUS Pence on many things, he acted in the best interest of the United States, which also turned out to be his best interest.
Generally speaking, unless you show clear intent to do illegal things, AKA not simple negligence on the part of a staffer, you won't be charged with national security crimes. People make mistakes and move on. When you do it repeatedly, brag about it, and then refuse to comply with requests to mitigate the problem, then destroy evidence, that's when people get charged with crimes.