Destiny 2’s cross-play beta will be held May 25-27.
The beta is true for all players on all systems Destiny 2 available on PC, consoles and Google Stadia. People can only participate in the Vanguard Strikes Cross Play Beta playlist. It is therefore not possible to create your own cross-platform parties during the beta.
Players who play three strikes in the playlist will receive a special emblem. which can be seen below. Cross-play should be available later this year with Season 15.
Bungie talks about the cross-play beta through a new blog post.

