IIRC, Chauvin made the plea deal on federal charges so that he would do his time in the relative safety of a federal prison.
Which would mean that if he gets pardoned on federal charges, then he would have to serve out his remaining state time in a state pen... the very thing he wanted to avoid. He would probably be dead in under a month unless he spent the next decade or more in solitary confinement for 23 hours a day (like he did in his pre-trial detention).
Which would be a crying shame, of course...
https://en.wikipedia.org/wiki/Algospeak