Word of the Mi Mix 3 has been scarce but there's a chance we get it sometime next month. There's also been word of another Snapdragon 710-powered Xiaomi device in the works.
https://www.notebookcheck.net/Mi-Mix-3-could-be-coming-next-month-with-some-of-the-slimmest-bezels-the-world-has-ever-seen.320836.0.html
Looks like the Mi8 was a huge mistake, now brands are lining up behind Oppo.