It's easy to forget with the roster from the first movie so firmly entrenched as the characters most people now associate with the Guardians of the Galaxy, but the team has actually had a few iterations in the comic books, just like the Avengers or X-Men. Granted, the membership has been considerably smaller than either of those teams due to the Guardians' lower profile in the Marvel universe, but it has included such notables as Adam Warlock (a big player in the Infinity Gauntlet/Infinity War storylines in the comics) and Captain Marvel.
A big question for Guardians of the Galaxy Vol. 2 is who might be joining the team for the upcoming sequel. While the movie has been described as a more intimate affair than the first outing, there has also been talk on more than one occasion of introducing new characters or having characters cross over from other MCU films. So far the talk of new characters has mostly been rumor, but that may change with an upcoming cast announcement.
The announcement will come next week, according to a video Q&A director James Gunn posted to Facebook. Gunn teased a new female member of the team, whom it is widely believed will be actress Pom Klementieff playing the telepathic martial artist Mantis:
"We have a new cast member playing a new member of the Guardians of the Galaxy and she was the most awesome and easiest person I’ve ever had to cast. She blew me the f*** away. She’s amazing, and I can’t wait to share her with the world."
Gunn added that the official announcement would be made "Next week I believe...Or at least most of them [will be announced]." Given the surge in recent Guardians of the Galaxy-related news lately, from the new logo to the script being finished, the timing makes sense. The release of the movie may be over a year away (preceded by Captain America: Civil War and Doctor Strange), but that doesn't mean Gunn or Marvel are resting on their laurels when it comes to the next outing for Star-Lord and crew.
The first Guardians of the Galaxy was a surprise success, taking one of the lesser-known Marvel comics and turning it into a fan favorite by offering what ended up not only being the most unique film from the MCU so far, but the funniest and most light-hearted as well. While sequels can often fall short of their predecessors, that has generally not been the case for Marvel's films, with Iron Man 3 and Captain America: Winter Soldier being very strong showings for the studio. Hopefully that trend will continue with the return of the Guardians.
Captain America: Civil War will release on May 6, 2016, followed by Doctor Strange – November 4, 2016; Guardians of the Galaxy 2 – May 5, 2017; Spider-Man – July 7, 2017; Thor: Ragnarok – November 3, 2017; Black Panther – February 16, 2018; The Avengers: Infinity War Part 1 – May 4, 2018; Ant-Man and the Wasp – July 6, 2018; Captain Marvel – March 8, 2019; The Avengers: Infinity War Part 2 – May 3, 2019; Inhumans – July 12, 2019; and as-yet untitled Marvel movies on May 1, July 10 and November 6, 2020.