Avengers: Infinity War gave the Guardians of the Galaxy a much bigger role than anyone expected. Despite it being known at the time that James Gunn was planning to take the helm of Guardians of the Galaxy Vol. 3, it left them in a very different place to where we last found them.
As you might expect, Gunn was consulted and obviously offered some input when the Russo Brothers put Avengers: Infinity War and Avengers: Endgame together.
However, when it came to who would break the news to the filmmaker that Gamora was to be killed by Thanos, writers Christopher Markus and Stephen McFeely reveal that it was Marvel Studios President Kevin Feige who sat down with Gunn for that particular discussion. Something tells us that it must have been a decision he was on board with, though, and it wasn't done for the sake of it.
In Gunn's Guardians of the Galaxy threequel, he will have the opportunity to pick up on the events of the last two Avengers movies to explore what happens next with Gamora. She left her timeline before ever meeting the likes of Star-Lord and Groot, and both killed her sister and betrayed her father in a future she was completely unfamiliar with.
Needless to say, that leaves Gunn with plenty of ground to cover a few years from now...