Well, technically Trump could simply issue himself a blanket pardon on his last day in office and then they couldn’t indict him for spit.
One of the not-very-well-known facts about whyTeam Obama’s illegal antics were allowed to spill over into the PDJT Administration is quite in synch with your thought.
Barry‘s top tier folk certainly would have wanted assurances that they wouldn’t be prosecuted for their following Barry‘s potentially criminal Directives, but such Directives’ coverage by Barry inherently couldn’t extend into the time window of the PDJT Administration..
Think about the disclosure that the three FISA renewals were deemed illegal well before a determination about the original was made.