The Division 2 will not be released on Steam
Ubisoft has its own Uplay launcher, which regularly releases its games on the PC. However, they did not bypass the Steve service from Valve. The coming The Division 2 will change this situation.
The publisher officially announced that the game will not be available on Steam. You can buy it on a PC in the Epic store and in the company's Uplay store.
However, there is a possibility that this transaction will be temporary, and in the future The Division 2 will still appear in the store from Valve. However, no specific information on this matter yet.