Trump pardons Dr. Melgen: Was a deal made?

Here's where it gets strange:
Trump pardoned Melgen on his way out in 2020.
Melgen was convicted of siphoning seventy three million dollars from Medicare, some of that money was being almost certainly being "donated" to top Democrats.
Did he make a deal with Trump? How interesting is it that Menendez escaped justice with a hung jury yet now in 2023 we have a money trail of literal gold bars showing a corruption that cannot be denied. Even people from his own party are demanding he resign as he stubbornly refuses.