First announced on December 14, 2017, Disney's acquisition of Fox and all its assets concluded on March 20, 2019. However, not only was Marvel unable to materialize any MCU X-Men introduction plans — the studio couldn't even start to outline any basic ideas involving Fox's former properties until all the legal minutiae were settled. Marvel Studios president Kevin Feige could only tease the mutants' eventual arrival at San Diego Comic Con 2019, and plans for the MCU's next three Phases after the Infinity Saga needed to move ahead with characters and stories that didn't explicitly involve the X-Men.