The Inhumans rumor was debunked.
Well, they say the film is still happening, but there's no saying it'll be as was planned.
I admit that change or inserting mutants into the MCU is unlikely, but you never know....Fox and Marvel working together's pretty unlikely too !
Here's the thing, though. Fox's movies may not hit the same heights as the Avengers, but they're still successful movies and fox doesn't have to share any of the credit or profit with Marvel Studios. They're not going to abandon the characters (and popular actors) that they have already pumped lots of time, effort and money into. And MS cannot include those characters in the MCU, because the two worlds are completely incompatible (unless they do some kind of limited crossover movie, like all the old Marvel/DC comics where inter-dimensional tears are threatening the fabric of the multiverse).
Maybe improved cooperation can lead to a little more leniency in edge cases or to some possible deal for FF (and supporting char.) rights, but it simply isn't possible for the MCU to bring in the idea of mutants (as seen in X-Men) at this point.