Various companies have begun teasing what we might see at this year's E3 expo. Blizzard has not historically had a big presence at the event, though. With the size and scope of Blizzcon, the company usually saves it announcements for then. In fact, I cannot think of a single, non-trivial thing that Blizzard did at E3 since the expo downsized after E3 2006.
This year, on the other hand, Blizzard will be present at AMD and PC Gamer's E3 show. The recent Overwatch previews could be leading up to this event, which takes place three weeks from yesterday. The recent video that I embed above, Tracer, is pretty interesting too. It shows how useful a light assault player could be if they don't obey the space-time continuum. The last two-thirds of the video show off an impressive kill streak.
Again, expect more E3 coverage leading up to the Expo on June 16th.