The latest developer update video from Blizzard's Jeff Kaplan reveals that Deathmatch is coming as a new mode for Overwatch. The mode and additional changes are available right now on the PTR.
Game director Jeff Kaplan reveals a new game mode coming soon to the Arcade: Deathmatch!

Play Deathmatch now on the PTR: http://blizz.ly/2vJuePP

00:15 - Why didn't we add Deathmatch before?
00:57 - Deathmatch is coming to the Arcade!
01:25 - Overview of Free-For-All Deathmatch
02:28 - What maps will be used for FFA Deathmatch?
02:51 - New map coming for FFA Deathmatch: Chateau Guillard
03:57 - Overview of Team Deathmatch
04:27 - What maps will be used for Team Deathmatch?
05:31 - Impact on Game Browser and Custom Games
06:34 - Never say never: Deathmatch is available right now on the PTR!