Marvel Studios head Kevin Feige has revealed the basic outline of the studio’s plan for the rest of the decade during which Marvel hopes the follow the model it is putting in place in 2014 with Captain America: The Winter Soldier (a sequel) and Guardians of the Galaxy, which brings new characters to the screen.  Marvel is repeating the pattern in 2015 by releasing one sequel (Avengers: Age of Ultron) and one film based on a new character (Ant-Man).  As Feige explained to IGN: "Guardians fulfilled our desire to do something different, to start producing, each year, a film that was the sequel to a pre-existing, successful franchise and do something new.  We're doing that next year with Age of Ultron, with Ant-Man, and hope to maybe continue that model in the coming years."
 
The revelation of Marvel strategy naturally has fans wonder exactly what "new character" film will follow the release of Captain America 3 on May 6, 2016 (when it will presumably go head-to-head with Warner Bros. Batman/Superman unless one of the studios blinks (see "Marvel Grabs Five More Movie Dates").  Much of the Internet speculation about the "new" character to be introduced to the big screen in 2016 concerns The Hulk, and in particular an adaptation of the Planet Hulk storyline that would involve the Guardians of the Galaxy, but Guardians director James Gunn crushed the rumors in no uncertain terms in an interview with Playlist: "There's not going to be a Planet Hulk movie, there was never going to be a Planet Hulk movie, there was never a plan for the Hulk to team up with the Guardians of the Galaxy--I wouldn't want the Hulk to team up with the Guardians of the Galaxy!  And it's all a bunch of complete bullshit."
 
Gunn explained the reason for the speculation is (minor spoiler alert) the presence of the Sakaraan, an alien race that features prominently in the Planet Hulk storyline, in the Guardians of the Galaxy movie.  But as Gunn noted the reason the Sakaraan were included in the GotG movie was that the original alien race for the Guardians storyline, the Badoon, "belong" to Fox because they first appeared in a Silver Surfer comic.  As Gunn put it, "there aren’t that many alien races in the Marvel Universe," and with the Badoon unavailable since Fox has the rights, Marvel Studios decided to use the Sakaraan. 
 
Bottom line, Marvel may well try to bring The Hulk back to the big screen, but it is unlikely to do so with the Planet Hulk storyline (at least anytime soon).