Update: Blizzard has announced Overwatch's newest hero Ashe is now available to play in the game.
Overwatch's official description for the character reads:
The 29th hero to join the Overwatch roster, Ashe — also known as Elizabeth Caledonia Ashe — is a gunslinger hailing from the American Southwest. Armed with the Viper rifle, Ashe is a versatile damage hero, able to fire rapidly from the hip or line up a high-damage shot through her sights. She blasts enemies by throwing dynamite, and her coach gun packs a major punch, knocking foes or Ashe back for added mobility. And Ashe is not alone, calling her omnic ally Bob to join the fray when the need arises.