X-Men is a superhuman mutant organization founded by Professor Charles Xavier for two reasons: first, to train the mutants to use their superhuman abilities, and second, mutants will serve as combat teams to defend humanity from attacks by other mutants who use their abilities to commit crimes, as well as against other threats.
The anticipated reboot of the MCU is approaching, so hopefully the X-Men will also be fully involved. There are actors and actresses who have appeared in the current MCU, but some would also be suitable for roles in the X-Men.