Blizzard just posted on its website that it won’t attend Gamescom this year to have more time and focus on games development. This comes much surprise for most potential attendees, seeing as Blizzard had always at least one half of the big halls reserved just for its own games. The news can potentially shrink down some of the space that gamescom has to show games to the players, as it may be unlikely that enough companies will come together to have a place at Gamescom that size or in amount to fill the space left open now.
On the other side it must mean something important when a company like Blizzard, that always was present as far as I can remember (this year will be the sixth Gamescom I’ll attend, third time as a press member even). Either the game development for titles like WOW Classic or other projects like a hopefully full Diablo 4 are some possible contenders for time intensive development projects that would extend past the usual promotion time that Gamescom would happen in.
Blizzard will very soon at the right time reveal to us what projects it is working on right now. You will still be able to buy Blizzard and its IPs merchandize on the official store floor in Hall 9 (if that’s the one they’ll always use). You can read the official statement right here: https://news.blizzard.com/en-gb/blizzard/22937753/blizzard-and-gamescom-2019