There is some overlap between existing achievements and co-op missions, however, achievements are only unlockable in the single-player version.
It’d be nice if the player could unlock those mission achievements on the co-op version. I find “achievement hunting” more rewarding when playing with friends!
Alternatively, some custom co-op-only achievements could be implemented! That’d be fun, there aren’t any currently in the game.
Co-op campaigns are a cool feature