Destiny 2 fans expected Bungie to reveal the next season and the subsequent expansion on June 9, 2020, but they delivered much more by shedding some light on expansions set for 2021 and 2022.
Bungie kept the next season's details secret until the big reveal on June 9 for some reason but that really wasn't necessary. We don't mean it in a bad way, it's rather that the studio heads revealed enough content to fill the stream properly while the new season ended up being a tasty cherry on top instead of the actual cake.
The cake itself consists of three expansions - Beyond Light in 2020, The Witch Queen in 2021 and Lightfall in 2022. We have already published some of the details from Beyond Light , including the visit to the Deep Stone Crypt where Exos were born, so to speak.
On the topic of the other two expansions, The Witch Queen is rather self-explanatory. We've killed Crota and then we killed Oryx. Savathun is pissed that we are trimming her family tree and is looking for revenge, but as Eris Morn explained before - she doesn't go into action head-on. The cunning daughter of the Taken King will probably come looking for the Guardians during autumn 2021.
According to Mike Noseworthy and Luke Smith, Lightfall will be somewhat different compared to the other expansions, at least narratively. Instead of a baddie that we are gunning for, we will be getting to know more about the origins of Darkness and Traveller. Considering how far away this expansion is, it's not really odd that they couldn't share more details.
However, there are a few notes that pertain to both expansions. Smith and Noseworthy stated that big twists can be expected in the expansions along with new destinations. By new, we mean brand new, not ones that are not recycled versions of the places we've seen before.
Furthermore, as new expansions come along, Bungie will be vaulting some of the older content that is not played as much as the rest. This doesn't mean the content will go away permanently as it will be reintroduced in subsequent content rotations, in hopes of keeping the install size reasonable and updating the game possible.