The thing about movie universes is that each film involved in it has to connect to one another in some way or form. The Marvel Cinematic Universe has not had any problems in this respect so far. However, the upcoming "Guardians of the Galaxy Vol. 2" is said to have little or no connection at all to the rest of the MCU.
From the very beginning, "Guardians of the Galaxy" was superhero feasts on its own. Its storyline was not heavily anchored to that of the other movies in the MCU and was not tied up to committing to any continuity. The story, unlike the other Marvel films, is set in outer space, which means nothing they do directly impacts the timeline on Earth.
There doesn't even seem to be any link to "Guardians of the Galaxy" to Thor through Asgard, which is perhaps the closest thing the Avengers have to an alien ally. The only thing that binds it to the rest of the MCU is Thanos and the Infinity Stones.
The events that transpired in the Marvel movies that came before "Guardians of the Galaxy" didn't show any effect in the movie. Similarly, what happened in "Guardians of the Galaxy" also didn't leak into the other films in the MCU.
Given that keeping up with the continuity was never an issue for the film, director James Gunn said that maintaining the same also would not be a problem for "Guardians of the Galaxy Vol. 2."
According to /FILM, Gunn explained on Twitter that "Guardians of the Galaxy" never really had to consider continuity so much because the story does not intertwine with those of the rest of the characters in the MCU.
In "Guardians of the Galaxy Vol. 2," the film will "focus more intensely on some of the characters," particular Peter Quill's (Chris Pratt) reunion with her dad, Ego the Living Planet, portrayed by Kurt Russell. According to Digital Spy, this plot will bring a very emotional element to the movie, so much so that it even brought Pratt to tears when he read the script.
"Guardians of the Galaxy Vol. 2" opens in theaters on April 25, 2017.