It’s confirmed the Guardians of the Galaxy – at least one member with Star-Lord – as well as the god of Thunder, Thor, will be appearing in The Avengers: Infinity War.
Joe Russo confirmed the news to the ComicBook.com web site.
On Star-Lord:
The movies are intended to be a culmination of everything that’s happened before in the MCU so you don’t want to get into spoilers but I’m a big fan of what James Gunn has done. [Joe Russo and I] are both big fans of what James Gunn has done. Star-Lord is a fantastic character and Chris Pratt is an awesome performer so you’d be very excited.
On Thor:
I’m excited to work with Thor. They’re doing some really interesting stuff with Ragnarok and where he’s gonna be at the beginning of Infinity War is gonna be a very interesting place and I think very profound. I think he’s gonna have a real emotional motivation after that.
It remains to be seen whether or not any of the other Guardians of the Galaxy characters make their way to Avengers: Infinity War. Interestingly enough, a while back a former Marvel employee that worked on the comic book told Cosmic Book News he/she expected the Guardians to be cannon fodder for Thanos.
And now we also know Thor survives Thor: Ragnarok.
The Avengers: Infinity War Part 1 has a May 4, 2018 release followed by Part 2 on May 3, 2019 directed by Joe and Anthony Russo.