Sony hasn't directly said that it would work with Microsoft and developers for cross-platform play, but it is willing to listen to developers interested in the service
Sony has responded to Microsoft’s invite for cross-platform play and has indicated that it is open to the idea. In a statement to GamesSpot, the company said, “PlayStation has been supporting cross-platform play between PC on several software titles starting with Final Fantasy 11 on PS2 and PC back in 2002. We would be happy to have the conversation with any publishers or developers who are interested in cross platform play”
While the response doesn’t directly say that Sony would work with Microsoft and developers for cross-platform play, it does suggest that the company is willing to listen to developers interested in the service. A few days ago, Microsoft had announced support for cross-network play what will allow Xbox and PlayStation gamers to play together. Rocket League is one of the first games to support the feature and allows Xbox One and PC players to play together.