Here’s a crazy possibility: Biden will blanket-pardon Trump to show how he wants to bring everyone together.
Or Biden will promise to pardon Trump under certain conditions.....
Comey suggested that. An acquaintence of mine who is a brilliant man suggested the same - he managed to get through Limbaugh's call screener and make this suggestion.
His logic is that it puts Trump in the rear view mirror and makes Biden appear magnanimous. "Healing" sort of idea. Versus indicting Trump or otherwise exacting vengence will make Trump a martyr and rally the people to favor Trump.