During the Overwatch All-Stars launch event, Blizzard Senior Designer Michael Chu confirmed that new heroes and maps are definitely in the works and will be coming "soon" to the game.
New maps and heroes confirmed soon by senior designer Michael Chu #overwatch #OverwatchAllStars pic.twitter.com/HpfDoN2u8a
— Valkia (@MarkPurdy1337) May 25, 2016
We'll keep you posted as more information is revealed.