Fortnite has turned on Xbone/PS4 crossplay. The interesting thing is they didn't announce it, it just happened. Given the previous issues between MS and Sony getting that turned on, there's speculation Epic just did it without permission. That could make sense, if they're banking on MS and Sony each not wanting the bad publicity of being the one to nix it, so just letting it continue. Other developers have said it's super easy from a technical perspective, it's just the company policies that have been preventing them.