Dems in a last ditch effort to claim Trumps scalp rather than let him leave peacefully, are asking VP Pence to relieve him of his office in accordance with the 25th amendment. Imagine he accedes.
Pence relieves Trump, per the Dems request, and assumes the presidency. His first act as President is to issue Trump a blanket pardon for anything and everything. Do the whole thing on the 19th.
Even better: Trump resigns on the 18th, Pence pardons him on the 19th, and both leave to play golf while Bejing Joe is sworn in on the 20th.