Question: are the primarchs coming back?
Answer: The return of the Primarchs, both traitor and loyalist has pretty much already been confirmed. ... However, there is a rumour that the traitor Primarchs will be the first to return so you might have to wait a bit before the Khan, Vulkan, Rogal Dorn, The Wolf King Leman Russ, The Raven Lord Corax and the Lion return.