Ashe, the new Overwatch hero Blizzard revealed at Blizzcon on Friday, is already live on the PTR. Here's her description, from the PTR patch notes:
New Hero: Ashe (Damage):
Ashe’s arsenal of weapons makes her a versatile offensive hero, capable of setting up the perfect situation to shoot down dangerous enemies from range or deal high area-of-effect burst damage to groups of heroes.
Her primary weapon is the Viper, a lever-action rifle with two firing modes: semi-automatic and aim down sights. In semi-automatic mode, the Viper shoots rapidly with a high spread. Aiming down the sights lets Ashe line up precise shots, increasing damage at the expense of speed.
She can turn any situation into her favor with her Coach Gun a short-range, high-impact sidearm that deals big damage and clears the way by knocking back nearby enemies. It can also be used to knock herself back for added mobility, either to reposition herself for a clear shot, or to escape pursuing enemies.
Ashe’s Dynamite ability is a thrown explosive that detonates after a delay. It deals damage in a wide radius and sets enemies on fire for additional damage over time. She can also shoot the dynamite to detonate it early, allowing her to damage unsuspecting enemies.
Her ultimate ability, B.O.B., sends Ashe’s loyal omnic companion rushing into the fray, shoving aside the frontline to rough up targets in the backline.
This update seems to be almost entirely for the sake of putting Ashe live, as the only other update in the patch notes is this: "Removed the “Unlock All” option in the Hero Gallery."
If you can't get into the PTR to try her yourself, be sure to check out all her skins.