UPDATE: The announcement has now been confirmed via today's live stream. The details remain the same, and nothing new will be revealed until E3 2018.
According to German site de.4-traders.com, Massive Entertainment is working with Ubisoft Annecy, Redstorm, Reflections, Ubisoft Bucharest and Ubisoft Shanghai to bring The Division 2 to life. The document contains a prepared statement from Massive Entertainment's Creative Director Julian Gerighty (translated via Google Translate):
We are very pleased to announce that we are currently working on Tom Clancy’s The Division 2. The development is led by Massive Entertainment and driven by close collaboration with Ubisoft Annecy, Redstorm, Reflections, Ubisoft Bucharest and Ubisoft Shanghai.
The Division 2 will be based on an updated version of the Snowdrop Engine that will help us realize our ambitions for this title. More importantly, we can also invest all the experience we've accumulated over the past two years in this sequel to make sure everything is going well.
All is not lost for The Division 1 either. It will receive a pair of new updates including Legendary difficulty, new global events and more as well as updated XBox One X graphics capability.