After spending a mere two weeks on the PTR (Public Test Realm), it would appear that the freshly added tank/support hybrid Brigitte is just about ready for her full debut. To be more specific, you can expect Brigitte to arrive for Quick Play and the Arcade on March 20th. No details have been given about her inclusion in Competitive Play just yet, but if past releases are any indicator she's most likely going to be sitting in the sidelines for a week before being truly unleashed upon the world.
[Update]: Apparently Brigitte won't be available in Competitive Play until Season 10. In other words, we still have 5 more weeks to wait before she's 'actually' in the game. A truly puzzling decision.
If you're interested in all of her abilities and lore, I would recommend you head on over to the official website as it contains pretty much everything you'll need to know in order to be ready for her launch. On the other hand, if you're more interested in her design and origins, allow me to share with you the most recent developer video narrated by the Lead Designer Ben Zhang. Have a look:
It's going to be interesting to see how much of an impact Brigitte has on the currently ongoing dive meta, because while her abilities are all incredibly potent, she is also extremely vulnerable to any sort of ranged pressure. While I have my doubts, I genuinely do hope she'll help break up the current meta as watching the same 5-6 heroes appear in every single game is not exactly my definition of fun time, especially in a game with as many unique and lovable characters as Overwatch.
Whatever the case may be, I suppose we'll find out soon enough as Brigitte will be available during Stage 3 of the Overwatch League! She might not have much playtime as the teams will still be inexperienced with her, but the few times she does appear will give us a pretty darn good indicator of her power level and the type of compositions she's good in. It's going to be an interesting stage, that's for sure!