On May 8, with the beginning of Season Three, we’re also launching the second expansion to Destiny 2. It’s called Warmind, and it will send you to new places to meet new heroes and battle new enemies. You’ll earn new loot and master new activities. Today, we’re naming it and dating it.
They simply went on to say that there will be a reveal stream on April 24 via Twitch. Maybe they will reveal something that's a bit more substantial that isn't completely and totally vague as "new loot" or "new activities."