https://www.gamespot.com/articles/sony-exec-talks-ps4s-new-cross-play-feature-and-it/1100-6462150/

Through Fortnite, console cross-play between Sony, Microsoft, and Nintendo is finally possible. SIE Worldwide Studios chairman Shawn Layden has provided additional background on why Sony changed its mind in regards to console cross-play, and has also revealed PlayStation 4's future with cross-play after Fortnite.

In episode 308 of PlayStation Blogcast, Layden says that despite Sony's public stance against console cross-play, the company has apparently been considering it for a while. "This is something that has been taking up about 65% of my Twitter feed over the last few months," Layden said. "Now, enabling cross-play isn't as simple as flipping a switch and there you go. It's a very multidimensional attribute or feature."