Tom Clancy’s Rainbow Six series is pretty storied. Siege was one of the more successful updates, featuring PvP gameplay. A new mode is set to run alongside it known as Quarantine. It was featured this year at E3, and for the most part, it was received well.
Ubisoft — in a recent earnings call — claims Quarantine will release by the end of this financial year. So, that means it will probably be here around March 2020 at the latest. Of course, this is based on development going smoothly. There could always be delays that push back Quarantine’s release.