https://www.gamespot.com/articles/fortnite-ps4-is-getting-cross-play-beta-starts-tod/1100-6462053/

Sony has announced that Cross-Play between PlayStation 4 and other platforms is coming to Fortnite. In a statement posted on the PlayStation Blog, the company said it has "identified a path towards supporting cross-platform features for select third party content."

"We recognize that PS4 players have been eagerly awaiting an update, and we appreciate the community’s continued patience as we have navigated through this issue to find a solution.