A preview showing a bit of Destiny 2, those who bought back in 07/18/2017, got the full early access to some missions.
Thos who didn't, were able to play only back in 07/21/2017.
In this video, I played a bit of the Story Mode available back then.
A curiosity about this version, was the fact that PSN Japan was providing full access without the need to buy the game. I had to use a PSN Japan account to get access to this beta.