Blizzard sent out the following

A new Overwatch feature, Role Queue, is now live on the Public Test Realm (PTR) on PC. Role Queue allows players to choose the role they want, with a separate skill rating for each role.
The Overwatch community is always evolving alongside the game, becoming more in tune with the game’s intricacies and discovering and sharing new high-level approaches to play. We’re introducing Role Queue to help ensure Overwatch matches continue to be fair and fun well into the future, and create an environment that fosters teamwork and encourages players to bring their very best to every match.

How Role Queue WorksWith Role Queue, we’re updating the matchmaking and queuing systems in Competitive Play and Quick Play so that players choose which role they want to play—tank, support, or damage—before a match even begins. The matchmaking system will then match two tanks, two supports, and two damage heroes to create a team, and upon entering match, players will select heroes within their chosen roles. At the end of a match (in both Competitive Play and Quick Play), players will return to the main menu and select their role before queuing for the next game.

Learn more about Role Queue at the link below.
https://playoverwatch.com/en-us/news/23060961
Watch Game Director, Jeff Kaplan share his thoughts on Role Queue in his latest Dev. Update here.

Role Queue and Overwatch Esports

A 2-2-2 role limit will be implemented in official Overwatch esports and in Stage 4 of the Overwatch League. To learn more about how Role Queue will change Stage 4 of Overwatch League play, please visit their full blog at the link below.
https://overwatchleague.com/news/23053245/