20th Century Fox and Marvel Studios are both in the business of adapting Marvel characters for the big screen, but neither side is known for working with the other. The former studio has long held the film rights to the X-Men and Fantastic Four properties, and since the latter studio has more than enough characters to fill out their cinematic universe, there hasn't been much need for cooperation between the two sides. However, it's now been revealed that Fox and Marvel struck a deal a while back to help each other out with Deadpool and Guardians of the Galaxy Vol. 2, which specifically involving the use of Negasonic Teenage Warhead and Ego the Living Planet.