In Marvel Disk Wars: The Avengers, they help Akira and his friends reach Loki's base in the North and fought the Sentinels while the kids went on ahead.
The X-Men have a film franchise since 2000, made by 21st Century Fox, making them the longest running superhero film franchise without a reboot. Despite being characters created by Marvel Comics, they could not be included in the Marvel Cinematic Universe, due to the rights being owned by Fox. With Disney's acquisition of Fox's assets and intellectual properties, characters from the X-Men films have been integrated into the Marvel Cinematic Universe through the multiverse plot, with the original actors reprising their roles, starting with Doctor Strange in the Multiverse of Madness, in which Patrick Stewart reprised his role as Professor X.