How many movies have Alexander T.H. Browne and James Gunn collaborated on?

They have worked on 4 movies together! Their first movie together was Guardians of the Galaxy Vol. 2 (2017) while their highest rated movie together was Avengers: Endgame (2019). They have not worked together since Avengers: Endgame (2019). They are most known for their science fiction films together.