Wolverine has long been the premiere X-Man. He's the team's most popular member, which means that he's the one Marvel crosses over into all the different titles. His popularity has seen him join every major team in the Marvel Universe, from the Fantastic Four to the Avengers. When he joined Marvel's premier superhero team, he finally embraced his role in the superhero community. No one ever thought Wolverine would become an Avenger but it was one of his best moves.
Source：https://www.cbr.com/wolverine-avengers-marvel-comics-fall-of-x/
