A lot of folks are jumping Mitchs azz about this, but I can't help but wonder just which "Former Presidents" he is actually referring to. Something about the wording leads me to believe he has a couple others in mind or is hinting at:
"JUST IN: Sen. Mitch McConnell: Former Pres. Trump "didn't get away with anything—yet.""We have criminal justice system in this country; we have civil litigation. And former presidents are not immune from being accountable by either one."

https://twitter.com/ABC/status/1360709957746843648