It’s finally happening. Sony, a company that is not known to back down from attacks on its arcane cross-play policies, has caved to pressure and will enable PlayStation 4 gamers to play against rival consoles with Fortnite. Sony has taken flak from gamers and industry figures (including Microsoft execs).
Fortnite is the most popular game

Source: Hot Hardware – Sony Backpedals, Will Enable Fortnite Cross-Play With Xbox One And Nintendo Switch