Leaked email suggests the deal between Epic Games and Sony Interactive Entertainment regarding the Fortnite cross-play announcement.
This was an exchange of emails from 2018 where Epic Games and SIE were planning to announce cross-play for the popular battle royale. The former suggested that when they will announce the cross-play feature, it would make SIE look good that it would make them “look like heroes.” It was believed that SIE did not like the idea of cross-play.
In exchange for approving cross-play feature, SIE would gain a lot of data and marketing data that they have asked for. It was also revealed that Epic Games offered to brand all of their E3 content with PlayStation. There were more deals too like gain exclusivity for a VR game at the launch of PSVR 2 and offers with PS Plus and Unreal Engine 4.
Epic Games and SIE does have a very close relationship, which is why it might have gone well rather easily with the deal.