Patents filed by Sony describing cross-platform play and digital in-game trading have surfaced leading to speculation that the upcoming PlayStation 5 console could possibly support these features. Details of how Sony would be implementing them is still unclear but the company could leverage its existing PlayStation Now service to enable these features with the support of developers.
https://www.notebookcheck.net/Sony-PlayStation-5-purported-to-support-cross-platform-game-play-and-digital-in-game-trading.415201.0.html