Feral Interactive have just announced that the Linux version of Total War: WARHAMMER II is due out 'as soon as possible' after Curse of the Vampire Coast DLC release for Windows.
With that in mind, Curse of the Vampire Coast is release for Windows on November 8th so it seems we don't have much longer to wait. Perhaps Feral Interactive will pull another XCOM 2 DLC, with their 'shortly after' turning into the same day which was pretty awesome. Pure speculation though of course, it could still be another few days or weeks after.
You can head over to the mini-site Feral Interactive put up for some more info. As a reminder, Feral Interactive also confirmed previously that it will use Vulkan which should hopefully mean it performs well.
Also, if you missed it, Feral Interactive recently put up a video showing Total War: WARHAMMER II running on Linux. I did a small write-up of what they talked about in this previous article, video included below for easy viewing.