The comic tells us of a new extremist group -- called Null Sector -- which seeks to go to war with the British government over oppressing omnic citizens, despite the integral part they play in providing manual labor and technical services to the British people. The result is an incident that takes place seven years prior to the game's timeline, and they're calling it the King's Row Uprising. It appears to be an all-out, urban battle between Null Sector omnics and members of the Overwatch team -- namely Blackwatch members like McCree. Gabriel Reyes won't really elaborate on what Blackwatch is doing on the ground before things pick up, but the comic leads up to Overwatch sending a strike team of it's members -- namely veteran members Reinhardt, Torbjorn, and Mercy as well as rookie cadet Tracer.
This brings us to this revealed trailer for the upcoming content in what appears to be called Insurrection, which is going to center around a new PvE mode somewhat similar to the one they had during the Halloween event. As stated before, the strike team is Reinhardt, Torbjorn, Mercy, and Tracer, and it looks like they're trying to push their way through a battle-torn King's Row to get to some kind of device set up by the combative Null Sector members. The star of the show seems to be the skins, which includes.
- Blackwatch McCree
- Blackwatch Genji
- Overwatch Reinhardt
- Overwatch Torbjorn
- Overwatch Mercy
- Overwatch Tracer
- Guerrilla(?) Widowmaker (pre-Talon, note the skin tone)
This is just from what I made out from the trailer, of course.