Xiaomi recently released the Mi Mix Alpha and that may have led some to believe that the Mix 4 was dead in the water. Apparently not, if new rumors are anything to go by. The Mix 4 is touted to be on the way, and it could come with the same 108 MP sensor we saw on the Alpha.
https://www.notebookcheck.net/Not-the-Mix-Alpha-The-Mi-Mix-4-is-said-to-still-be-on-the-cards-with-a-108-MP-camera-onboard.435683.0.html