A month ago Overwatch got its first new hero, Ana. Two weeks later its first seasonal event started with the Summer Games 2016. And now Blizzard has announced at Gamescom that next month the game will be getting its first new map, Eichenwalde.
Eichenwalde is an assault/payload hybrid map centered around a castle in Germany of the same name. The attacking team has to escort a battering ram to break down the castle doors and then most likely capture a point beyond that, which would make it the first "reverse" hybrid map in the game. [Update: Looks like this isn't the case, and it's a standard hybrid map with a capture point before you push the payload.] Blizzard said that the middle section of the map is a also little different than previous maps, as it plays with height a lot more than usual.
Lore wise, Eichenwalde is the site of "one of the most famous battles during the Omnic Crisis." Balderich von Alder—leader of the Crusaders, the group Reinhardt was a member of before joining Overwatch—held out against an overwhelming number of omnics before being killed, and his remains are visible in the throne on Eichenwalde's final point. The attackers are trying to recover Balderich's remains, while the defenders are trying to stop them.
Beyond that, Blizzard also said that Eichenwalde is actually the place where Bastion suddenly came back to life. Bastion's Origins skin is covered in grass and plants, and you can see other Omnics that look like Bastion still in a similar state scattered around the map. There will be a new animated short all about Bastion's origin story soon, so I imagine we'll be seeing more of Eichenwalde shortly.