Director of Product Management for Xiaomi Global, Donovan Sung, has posted a photo of the upcoming Xiaomi Mi Mix 3 that shows the handset operating on a 5G network. The Mi Mix 3 will be one of the first phones to support 5G when it launches in October this year, much ahead of time even before 5G networks actually rolling out.
https://www.notebookcheck.net/Xiaomi-Mi-Mix-3-will-be-compatible-with-future-5G-NR-networks.328750.0.html