Josh Trank takes inspiration from the artwork by Bryan Hitch in The Ultimates - the Ultimate Marvel Comics version of The Avengers. The grounded approach, characters and origin story of his Fantastic Four movie reboot is based largely on the Ultimate Fantastic Four (read about the differences to the original team here). That means a new origin story, a younger team and even a different team dynamic.
Given that the Ultimate X-Men comics are also used as a source of inspiration for the X-Men films, it’s easy to see potential future connections between the properties and why Ultimate X-Men and Ultimate Fantastic Four co-creator Mark Millar was brought into the fold by the Twentieth Century Fox as a consultant on their own Marvel universe.