According to a new leak, OnePlus' next phone will have a rear panel that, while superficially like that of the flagship 10 Pro, will house different cameras and seems to be made of significantly different materials. It will reportedly launch as a member of the OEM's new Ace series in China, although it may come to other markets under a different name.
https://www.notebookcheck.net/OnePlus-Ace-is-slated-to-gain-a-new-Racing-Edition-with-a-possible-Standstone-finish-in-plastic-thanks-to-a-new-leak.618382.0.html