After some speculation from fans, Deathloop director Dinga Bakaba confirmed that the game is in fact set in the same world as Dishonored.
Arkane's games all tend to have some similarities here and there, being one of the few big developers to actually make immersive simulators, but Deathloop and Dishonored obviously shared some DNA in more obvious ways. But according to Deathloop's director himself, the games are both in fact in the same world, something likely to please fans that have theorised as such.
Bakaba confirmed the connection on the most recent episode of the Xbox Podcast (thanks PCGamer), where he said that Deathloop is "one of the futures of the Dishonored world." Asked directly about the connection, Bakaba noted how due to the nature of the game not everyone will see the same thing, "so it was nice to see the community pick up the little clues that we did sprinkle everywhere that, yes, indeed, we envisioned Deathloop to be happening in the future after Death of the Outsider."