James Gunn has left an indelible stamp on the MCU with his Guardians of the Galaxy trilogy.
With Guardians of the Galaxy Vol. 3, James Gunn will attempt to bring all these different character arcs to a satisfying conclusion.
So it is entirely possible for there to be a Guardians of the Galaxy movie not featuring the characters that appear in James Gunn trilogy of the franchise.
For diehard MCU fans, the thought of a Guardians of the Galaxy movie without Starlord, Gamora, Drax, Rocket, Mantis, Nebula, or Groot would be unthinkable.