Conveniently just after Overwatch received its Competitive Play update, Valve has announced the Meet Your Match update to Team Fortress 2. This update includes Competitive Mode, which is a ranked, 6v6 gametype, which sounds even more like Overwatch. Only the first day has been revealed thus far, as Valve likes to break update posts into chunks and release them over the course of a week, but it includes three maps, two achievements, and the official launch of the PASS Time game mode. The second part of the update is coming soon.
PASS Time was originally announced last year, in collaboration with Bad Robot (J.J. Abrams' production company) and Escalation Studios. While I've never played it (yes, I pretty much only play 2Fort…) it sounds similar to game modes like Bombing Run or Grifball. Obviously, those game modes are typically for more individual shooters, not TF2's class system, so it's interesting to see how, for instance, a Level 3 Sentry plays into it.