In one corner there are the X-Men, the mighty team of mutants who seek to protect humanity and create a world where the two can peacefully coexist. In the other corner, there are the Avengers, Earth’s Mightiest Heroes, who seek to protect the world from those who seek to rule or destroy it. Both teams have storied histories on the comic book page, and both have starred in wildly successful, innovative cinematic blockbusters — but in both cases, they’ve kept mostly to themselves.
This is easy to understand in the films, where intellectual property ownership has largely kept the properties apart for legal reasons. But even in the comics, where crossovers and cameos are extremely common, the two teams often feel like they exist within their own separate worlds, each franchise telling its own tales without stepping on the other’s toes.