So with sunsetting bungie killed off the Red War storyline (how you first got introduced) unfortunately. So whatever stuff happened in New Light is basically how you're introduced to the game now. Speaker's been missing since D2s start (so you haven't missed much there, that was all the explanation we got too) and you can still play the Forsaken campaign, which is where Cayde dies. Shadowkeep should still be available too. I do recommend playing Forsaken's campaign, its very good.