According to multiple sources, Bungie is planning to attend E3 2015 next month.
In what manner the studio will be showing off its content is unknown; it could be via press appointments at Activision's booth, or it could be a reveal at one of the big press conferences. Either way, if you put two and two together, it's not difficult to figure out what Bungie's going to be showing.
For months, we've known that Bungie has a long-term plan for the first Destiny game, including at least five expansion packs. The third pack is expected to drop this fall, and based on a leaked slide from an internal Bungie meeting, we know that this pack is going to be the biggest and most important of them all. Kicking off the online game's "Year 2," the leaked image labeled the third expansion Plague of Darkness, though this name could easily be changed before it's released.
Based on insider information, Plague of Darkness will be basically Destiny 1.5, a major release much bigger than the other expansion packs but not quite as huge as Destiny's core game. Plague of Darkness is believed to introduce a third sub-class for Guardians, two new weapon types, 12 new Story missions, a new Raid, new Strikes and it could see a big increase in level cap.
In related news, Bungie revealed today that High Moon Studios has been doing side work on Destiny. High Moon is best known as the studio behind Transformers: War for Cybertron and Transformers: Fall of Cybertron. It's not known exactly what the studio is doing for Destiny, but it's very common for publishers to farm out content on triple-A titles to adjacent studios this way. High Moon's contributions could be anything from character and gear design to full level creation.
So, it looks like Bungie will be bringing Plague of Darkness to E3, or at least some part of it. We're expecting to see a trailer teasing the DLC's story or possibly on-stage demos of new gameplay.