Alan Wake is the focus of Control's AWE expansion
The decidedly strange events that took place in Alan Wake—in which a famed author traveled to Bright Falls, lost his wife, encountered some shadow monsters, hung out with a weird Viking heavy metal band, and got sucked into another dimension—were actually part of an Altered World Event in Control.
FCB agents investigated the incident and brought materials back to Control headquarters for study, but then it all went sideways somehow and the entire Investigation Sector had to be sealed off. In the AWE expansion, new Control director Jesse Faden will try to reopen it, which will presumably lead to the encounter with Alan Wake.
While it's certainly been assumed since Remedy unveiled the Control roadmap, it's amazing to finally have confirmation of the tie-in between the two games.
While playing Control, I couldn't help but think the door with the spiral on it, which appears in the motel you visit during several intermission-like sequences, had something to do with Wake's eventual return. Presumably, the others are tied to other titles in Remedy's catalog, like Quantum Break (which makes several references to Alan Wake), and games that don't even exist yet.