Although it takes place in the Marvel Cinematic Universe, Guardians of the Galaxy felt largely separated from the other Marvel properties. Other than a Thanos cameo, a full introduction to The Collector and brief shots of familiar aliens and the Infinity Stones, the film is a very self-contained story, which may have been part of the reason it was so successful among audiences in August. With Guardians of the Galaxy 2, director James Gunn is intent on keeping the same formula, which as a consequence means there won’t be any connections with some other upcoming Marvel movies.
While chatting with MTV about the upcoming Blu-ay and DVD release of Guardians of the Galaxy, Gunn mentioned that future plot points in the MCU won’t affect the story he’ll be telling in Guardians of the Galaxy 2, which is set for release on May 5, 2017. Said the filmmaker,
"I don’t feel beholden to that stuff at all. I think it’s really about the Guardians and what they are doing. We’re not subservient to the Avengers. Guardians 2 is not a movie that’s made to move toward [The Avengers:] Infinity War. It’s something that’s made to move toward future cosmic movies, so I don’t feel that that is something that affects me that much."
So if you were expecting Hulk to pal around with the Guardians or see a post-credits scene setting up Avengers: Infinity War Part I, prepare to be disappointed. It’s unclear whether this also means that the Guardians won’t be fighting alongside Earth’s Mightiest Heroes against Thanos, although given that the 2018 film is meant to be the culmination of everything that’s happened in the MCU since 2008, it would be odd if the only heroes fighting the Mad Titan were those in the Avengers lineup. It may still be too soon to count out last minute assistance from the ragtag Guardians.
It’s understandable that Gunn wants to keep the cosmic side of the MCU separate from what happens on Earth, but given that Thanos will be the big bad in both Infinity War films, it’s hard to believe there won’t be more cosmic elements in the film other than him and the Infinity Stones. Guardians of the Galaxy 2 might not be "subservient" to the Avengers films, but eventually what happens out in the rest of the universe will start to affect Earth. While the sequel’s narrative will probably be as self-contained as its predecessor, I wouldn't be too surprised if Marvel has Gunn throw in some hints of what’s to come that the hardcore fans will pick up, but won’t distract the viewers not obsessed with the intricacies of the MCU.
Just remember that Guardians of the Galaxy 2 probably won’t be the only Phase 3 movie set in space. In 2017 we will also see the release of Thor: Ragnarok, where the legendary apocalyptic battle will have enormous ramifications not just on the Asgardians, but on the entire MCU. If Guardians of the Galaxy 2 won’t help lead into Avengers: Infinity War, perhaps Marvel will turn to the Norse gods to get the job done.