will guardians of the galaxy be avengers

Do you think the Guardians of the Galaxy will be in the next Avengers film because they have one of the stones also why would Marvel make GG if they did not have a role to play in the big picture because all the other Marvel movies so far seemed to have been introducing characters who join the Avengers.

So will GG be in Avengers and if they do how it worked into the plot because the Avengers are all human and they are serious characters the GG are not

How do you make a tree an Avenger