'Although Marvel has traditionally announced release dates for its movies several years in advance, it has been more secretive about its plans for the Marvel Cinematic Universe after the current Phase 3 ends. Spider-Man: Homecoming 2 is the only movie with an official release date after Phase 3 closes with 2019's Avengers 4, but we now know that Guardians of the Galaxy Vol.3 will be released in 2020.
The news comes via director James Gunn, who helmed the first two Guardians movies and will direct Vol. 3. Gunn was asked by a fan on Twitter about a third film in the space fantasy series, to which he replied "coming in 2020." - via GameSPot
The Guardians will be part of the SUPER wicked and very anticipated, Infinity War film coming May 4th, 2018.