https://www.gamespot.com/articles/overwatchs-new-map-rialto-is-launching-this-week-f/1100-6458660/

The newest Overwatch map, Rialto, will launch for everyone on May 3, developer Blizzard announced on its website. The map was initially released back in April on Overwatch's Public Test Realm for the purposes of testing before its public release.

The new map comes to Overwatch just after Season 10 of Competitive play, which started today, May 1. However, Rialto will not be available for Competitive play until a later date. "This will help provide the community with plenty of time to learn how to play with the new map," Blizzard said.