After two solo films and major roles in Avengers: Infinity War and Avengers: Endgame, and an upcoming third feature, the group has gone through its share of battles together, but figuring out who’s in charge can be confusing at times, especially with the potential addition of Thor at the end of Endgame and a possible power struggle between him and Star-Lord. So who is actually leading the team?
There is no set "leader"
Peter Quill is the nominal "Captain" (and thus "in charge" in his mind) because it's his ship they are riding in but these people are together by choice and decisions, at least from what we have seen, are made as a group.
They all have their input and if one of the group disagrees they are free not to take part.