GamesCom kicks off next week, August 23-28, in Cologne, Germany and Blizzard's planning to reveal some awesome stuff for its fans! For Overwatch, Blizzard plans to reveal a new map and a new animated short. The map preview will go live on August 21, while the animated short will become available when GamesCom opens on August 23. Overwatch game director Jeff Kaplan has mentioned a new map would be coming and that it would be based on the childhood home of Widowmaker, aka Amelie Guillard LaCroix.
As for World of Warcraft and Hearthstone, a new patch, with details, will be shown off for WoW and new Fireside Gathering features for Hearthstone players, plus a new group raid for the CCG featuring the Lich King. As for Heroes of the Storm, a new hero will be added to the game and more.
Blizzard's posted their full schedule for GamesCom on their website, which you can view here.