[Update]: Orisa has now arrived to the live servers (both PC and consoles) alongside a sizable balance patch!
Overwatch's 24th hero Orisa spent the past three weeks on the PTR, and after a surprisingly low amount of changes she is now finally coming to the live servers as well. To be more specific, you'll be able to mess around with Orisa at some point later today, most likely three hours from now.
However, according to Blizzard's recent announcement you will not be able to choose Orisa in Competitive Play for an entire week after release. But worry not, she will be fully available in every other game mode: Quick Play, Arcade, Play vs AI, and even in custom games.
While this isn't a massive change, it will at least ensure that Competitive Play doesn't turn into a complete clownfest like it did when Ana and Sombra first arrived. I'm still not sure if one week will be enough for people to master everything Orisa has to offer, but its certainly a step in the right direction and a great change for everyone who wanted to play some 'proper' Overwatch throughout this week.