Jeremy Renner attended Wizard World Comic Con Chicago and made a comment during one of the panels that can not be taken lightly, regarding Guardians of the Galaxy and the Avengers crossing paths.
ComicBook.com reports that Renner “seemed to indicate” that there weren’t any plans in the works to merge these characters. He said he assumed Marvel was planning on giving the Guardians another movie (yes, we know, scheduled for a theatrical release on May 5, 2017), “and then we’ve got Infinity War” (as if those movies belong to Avengers characters only). Joking about when the crossover might take place, he said to one poor kid: “You’ll be 80 years old by then, and I won’t be Hawkeye anymore. I’ll be Dead Guy.”
Dead and still not funny, and dead wrong! Everybody knows Guardians of the Galaxy is considered part of the MCU Phase 2. In the first movie we encounter Thanos (who is planning to attack the Earth since
forever the credits of Avengers 1), the Collector (also seen in after the credits of Thor: The Dark World) and the Infinity Stones which are all over the Avengers movies. Gamora of the Guardians is also the adopted daughter of Thanos and in the comic books she is a member of the Infinity Watch, a group that is guarding the Infinity Gems from being assembled into the Infinity Gauntlet. I can only assume the Infinity War is going to have something with those Gems and then there is no way some kind of crossover meeting will not take place.