A possible Xiaomi Mi Mix Flip or similar could be in the works according to a recently granted Chinese patent for the company. Technical drawings included in the patent application show the Xiaomi clamshell smartphone has seemingly been inspired by both the Samsung Galaxy Z Flip range and the Redmi Note 9T.
https://www.notebookcheck.net/Xiaomi-blends-a-Samsung-Z-Flip-with-a-Redmi-Note-9T-to-come-up-with-a-potential-Mi-Mix-Flip-clamshell-smartphone.548663.0.html