So that trailer in Watch Dogs 2 that nobody could make heads or tails of? Turns out it was just Beyond Good And Evil 2 all this time.
The original trailer could be watched by completing the Ubistolen mission in Watch Dogs 2, in which you would hack into the Ubisoft San Francisco offices and download an unknown game trailer that the execs were scared off being leaked too early to the public. Watching the video, we can clearly see that it's a space game of some sort, but the gaming community were unsure as to what game it could possibly be showcasing, or if it was just a joke by Ubisoft. At the time, they never made any comments on this trailer, but fast forward to E3 2017 and I'm pretty sure we all know the answer to that now.