At the start of Season 1, Octane was added to the game as the new Legend and for the next season, we will be seeing Wattson as the newest addition to the game. There were lots of leaks about her ever since the first season of the game started. Supposedly she is going to be electricity-themed Legend. Respawn Entertainment’s panel at EA Play 2019 will reveal the champion or at least there will be some discussions on her.
There is not even a piece of single information on her abilities and playstyle but during one his streams, Shroud stated that he didn’t like the Legend all that much and said “it’s not gonna be that sick” about Wattson.
As far as her introduction date to the game goes, it is unknown and it’s highly unlikely that we will be seeing her before Season 2 starts. With more and more on features on the way, next season is going to be full of content, new features, and maybe map changes or even an entirely new map. You can learn more about what to expect on Season 2 from here.