While Gunfire Games' sequel, Remnant II, had a pretty impressive launch, dwarfing what Remnant: From the Ashes ever managed to achieve on PC at the least, the game was lacking crossplay at release. Fortunately, it doesn't look like it will always miss the feature, as speaking in a Reddit AMA, game director David Adams revealed that Gunfire is working on bringing crossplay to Remnant II at the moment.
Specifically, Adams stated, "Yes, we are looking at it. There are issues with the different platforms and what they require in order to allow crossplay, but it is being actively worked on."
Essentially, expect Remnant II to one day support crossplay, but as for when exactly that day will be, there doesn't seem to be a timeline put on when the feature will debut within the sequel.
Further on in the AMA, Adams also confirmed that more archetypes are planned as DLC down the line, that the ping pong gun is his favourite weapon, and that there are "a lot of plans and schemes for the franchise" but Gunfire is currently focused on building up and tightening up the current game.