It looks like the Inhumans movie may be happening after all, just not anytime soon. Marvel Studios famously plans their movies out way in advance and announces their plans to the public long before their release date. Kevin Feige has been perfectly willing to shift around release dates when necessary, which is what happened with Inhumans. The original July 12, 2019, release date for the movie was scrapped and no other release date was confirmed. So, it sort of seemed like the movie simply wasn't happening.
Kevin Feige has been making the rounds doing press for Doctor Strange. Speaking with /Film, the Marvel Studios president revealed that Inhumans is still very much in the cards, but it won't happen until Marvel Phase 4 at the earliest. Here is what he had to say.
"I think Inhumans will happen for sure. I don't know when. I think it's happening on television. And I think as we get into Phase 4 as I've always said, it could happen as a movie. I think it would be super cool."
There has been something of a divide between Marvel TV and the movie side of things. While the projects all technically take place in the same universe, there has been very little crossover between the two so far. So even if Inhumans does happen, it probably won't have anything to do with what has already happened on Agents of S.H.I.E.L.D.. With Marvel getting to make Spider-Man: Homecoming and deciding that a sequel to Ant-Man was a good thing to do, they had to make room in Marvel Phase 3for those things. Something had to go and Inhumans seemed to make the most sense. Not only that, but putting the movie out later will help distance it from what happened on Agents of S.H.I.E.L.D..
Inhumans debuted in Marvel Comics back in 1965. The main story followed a royal family of super beings ruled over by their silent king Black Bolt, whose voice is capable of destroying cities. There have been long-standing rumors that Vin Diesel will play this mute character in live action, while he voices Groot in the Guardians of the Galaxy franchise. Quiet in front of the camera and only saying a few words behind the camera seems like a good way for Marvel to utilize his talents. The young members of the Inhumans get their power from ingesting Terrigen Mists (because comic books). This idea has been introduced and developed in Agents of S.H.I.E.L.D., which some speculated was why the movie was initially pulled from Marvel's release schedule.
As of right now Phase 3 still has a lot to offer. Guardians of the Galaxy Vol. 2, the previously mentioned Spider-Man: Homecoming and Thor: Ragnarok are all due out next year, plus the massive Avengers: Infinity War is looming, with the untitled Avengers 4 coming as well. Disney has three release dates pegged in 2020 for unannounced movies on May 1, July 10 and November 6. Those seem like prime Marvel dates, so maybe one of those will wind up being Inhumans.