I've had it on the Preorder Listing for weeks with a December 12th release date. The Amazon link is not active, but I expect it be so come next week.Just got a press release that the Blu-ray for the first season is coming out next Tuesday, Dec. 12th.
Seems kind of short notice, and there's not even an Amazon listing for it. But looks like it got delayed a couple weeks based on this article from October. https://screenrant.com/luke-cage-season-1-coming-to-blu-ray-november-2017/