Blizzard recently confirmed that they are working three upcoming Overwatch maps, and now we may know the identity of the first one... sort of. GamingBolt has reported that data-mining has been underway since June of last year, and now some results show that an upcoming location could be in space.
Specifically, several audio cues reveal the character Winston talking about "the moon", as well as space-like audio effects.
Of course, the Horizon Lunar Colony is already an established location in the Overwatch universe, as it's where Winston was raised. We can only hope that this is where we're headed next.