Along with serving on that team of mutant superheroes, Russell was also a member of the X-Terminators and New Mutants, but he was later brainwashed by the Mutant Liberation Front.
Introduced in 1986’s X-Factor #1, Russell Collins mutant ability emerged while he was serving in the Navy, and although the military police quickly apprehended him, he was rescued by the X-Factor.
Eventually he was freed from that brainwashing by Magneto and joined the Master of Magnetism’s Acolytes in gratitude, but soon after he was killed by Holocaust, a mutant villain from the Age of Apocalypse reality.
The name Russell by itself doesn’t help much, but when looking up any characters from Marvel Comics with that name, as well as taking into account that Deadpool 2’s Russell can generate fire, it looks as though the movie is featuring a version of Russell Collins, who is also pyrokinetic.