“Kurt Russell [Ego the Living Planet] in the new Guardians movie was the character that Fox swapped with Marvel to [change] Negasonic Teenage Warhead powers.”
There’s also rumours that some tricksy negotiation may have happened to allow Marvel/Fox to produce the X-Men-related Legion TV series.
However, a tongue-in-cheek approach and resulting box office success aren’t the only links the two surprise hits share; it turns out that creative choices in the writing of Deadpool had a direct influence on the plot of Guardians of the Galaxy Vol. 2.
That or collaborate directly and share the wealth, like what they’re working with Sony on Spider-Man: Homecoming.