I don’t like MMA but the Undisputed series kicks ass. First one is boxing and it’s Ving Rhames and Wesley Snipes. Ving is based off Mike Tyson I believe.
Second one is Michael Jai White and I believe he is supposed to be Ving Rhames character from the first movie. It goes into MMA here and introduces Scott Adkins.
The third and fourth movies Scott Adkins is the protagonist.