Bungie announced pretty much everything of interest about Destiny 2's Season 13 and that includes three strikes, of which only one is brand new.
Destiny 2 is getting a lot of recycled content once again and there are two strikes among other stuff. Fallen S.A.B.E.R. and Devil's Lair are making a return.
It is difficult to discern whether these will be copy-pasted from the original Destiny or repurposed for Destiny 2 since the descriptions are extremely close to what the Guardians saw previously. Furthermore, if they are indeed just the same old strikes from before, it will pose even more problems with continuity and cause more confusion among the players, should they try and figure the state of the game world.
Namely, Devil's Lair has you going up against House of Devils, who are supposed to be on Europa mostly since Eramis took them there previously, in order to give them the power of creating icicles and snowballs.
Meanwhile, Fallen S.A.B.E.R. description states Rasputin is asking for help, which is literally the same scenario as in the original Destiny. Considering the events of Beyond Light, it's odd to hear the AI speak at all, to say the least.
Anyway, there will be one genuinely new strike - Proving Grounds.
The description on the preview page for the season only states that the champions of humanity will face the champions of the Cabal to determine the fate of the Last City. It's ambiguous but if we're talking about literal champions, we will probably need a lot of Unstoppable mods.