Source: IGNSpeaking to IGN's Brian Altano during our E3 Live show, Watch Dogs: Legion creative director Clint Hocking said "There are no dogs in the game because if you're gonna play as anyone, we would have to be able to support playing as a dog, because that's only fair."
Watch dogs 1 didn't have any dogs but after some well deserved criticism they put them in watch dogs 2, it is now confirmed that dogs won't be back for the 3rd game. It looks like there won't be any cats either but I'll update if I catch one.
Hype went down a bit not gonna lie, Ubisoft pls.