Bungie seem to be preparing to launch more story content for Destiny 2 with a major enemy from the original Destiny returning. It's currently unclear how it will fit with the recent reveals regarding the Trials of Osiris. Spoilers ahead!
Destiny 2's story is ripe to progress further but it's still doing so at a snail's pace. Bungie may or may not shake things up with Season 11 since they have two exciting plots ahead of us but given the history of Destiny story development, it's possible nothing will be resolved and these two might just be superficial additions.
The first bit of Season 11 story elements that leaked is pertaining to the Trials of Osiris lore that hints at the return of the Darkness. It sounds like a big deal but we knew it had to happen at some point, with that teaser at the very beginning of Shadowkeep. Furthermore, this may turn out to be just a prelude to a bigger story arc after Season 11.
Anyway, the more immediate plot seems to be happening on Earth itself. A data miner going by GinsorKR found several indicators that SIVA will return. The self-replicating plague that once benefitted mankind already has some model assets .
On top of that, the same data miner uncovered text that reveals what we might find in the new bit of content. A new PvE activity is apparently called Observatory and several indicators were found that point to the resurrection of Lord Felwinter , one of the Iron Lords.
One might think this is getting out of hand with all the dead characters coming back to life but since SIVA will be the big baddie here, it's possible things are not as straightforward as with Saint-14 for example.
SIVA already resurrected Sepiks, one of the Fallen servitors, and there is a possibility something similar will happen with Felwinter too. If this happens to be the case, we might need to fight the former Exo that sought peace once upon a time.