Season 10 of Overwatch competitive play has now arrived, though unfortunately the Hanzo rework and its accompanying balance changes have not yet left the test servers. On the positive side, Brigitte has now finally become available in competitive play, which should shake up the meta quite significantly. Whether that is a good or bad thing, that still remains to be seen.
As far as the new payload map Rialto is concerned, you can expect to see it released on May 3rd. It's not going to be available in the competitive rotation until a future patch, but that's probably for the best given how confusing it can be to play on a completely new map, especially in competitive.
On the other hand, competitive 6v6 Elimination will only continue to be active until midnight (UTC) on May 7th. So if you're up for trying out some new heroes, or just collecting a bunch of extra competitive points, do make sure to give it a look before it gets sealed away. As always, your rewards will be based on your season high, though Top 500 players will need to maintain their rank until the end if they wish to receive that fancy icon and animated spray.
Finally, it's also worth mentioning that Blizzard has detailed their plans for Symmetra's rework into a Defense hero. There is no easy way to summarize this since all of her abilities and weapon attacks are being changed, but if you're interested you can head on over here to learn more.
And with that said, I wish you the best of luck with your placement matches!