It has been a hallmark of presidents in the US to never, ever, go after the previous administration legally for whatever infractions may have occurred.
It is a gentlemen’s agreement but one that serves them all well. Every administration, to some degree, has skeletons in their closet and none want to take the job knowing a future administration that does not like them will trot all of that mess out.
I cannot think of a single instance when a new president and his administration went after the people in the previous administration (this is where the SDMB will school me probably).
But Trump has gone to an all time low. For the sake of this argument assume Biden wins in November. Will Biden tell his AG to prioritize the Trump admin for wrong doing or will Biden make some speech about how this will not serve the country well and we just need to move on?
My money is Biden leaves the Trump admin alone and goes with the “we need to move on and heal” spiel. Maybe throw some minor functionary under the bus to make it look like he did something.