Helldivers 2's developer is potentially open to collaborations with others games, but it would be very dependent on which games.
A Helldivers 2 player recently asked developer Arrowhead about potential future collaborations in the game's official Discord channel. Community manager Twinbeard says that while Arrowhead looks at potential crossovers with "interest," it also needs to be very mindful of the game's "fantasy and lore."
