We all know by now that Marvel's movie lineup has some exciting features coming up for us (Civil War, Spider-Man, Infinity War), and the lineup ends right at 2019's Inhumans. But what's after that? What's the most likely thing(s) to do after such an action-packed schedule? We can only take estimates, assuming Inhumans will not be the last MCU movie.
World War Hulk
Mark Ruffalo plays as The Incredible Hulk in the MCU, and it's said that Ruffalo would be the only actor to be in both Infinity War movies. Plus we haven't had a Ruffalo-Hulk movie yet (since the last one was 2008's The Incredible Hulk with Edward Norton), so this would seem suitable and wonderful for his first appearance. Not to mention it's such a great comic book.
After the lineup was changed, Spider-Man was added for a 2017 release date, meaning Peter Parker would appear...and possibly Norman Osborn. If Osborn does appear, then Secret Invasion would seem sensible. The Illuminati are banded together to fight the Skrulls, a shape-shifting breed of alien, and makes a mission that will make you wonder who to trust. The only part of this I can't see is The Fantastic Four and X-Men appearing because...well, I don't need to explain that one.
Secret Wars (1984)
Secret Wars was a pretty game-changing crossover, and plus X-Men and Fantastic Four can just be replaced with GOTG and Inhumans. Beyonder kidnaps certain heroes and villains from Earth to fight on his own planet. But the heroes soon assemble to defeat Beyonder.
Thor, Cap, Spidey, and so much more! After Norman Osborn created the Dark Avengers in Dark Reign, him and the DA go to Asgard to invade. Again, we would have to see Osborn in the upcoming Spider-Man film, but still, that would be an amazing crossover.
After Jon Bernthal was cast as The Punisher for Season Two of Marvel's Daredevil, the character seemed likely to appear in a solo film or in one of Marvel's many upcoming crossover events. The Punisher takes revenge after his wife and children were killed by the Mob, and is an anti-hero type person. It would be awesome to see him and Crossbones fight it out though. Just imagine it.