OnePlus will unveil its first-ever concept device at CES this year. Given the prevailing smartphone trends, it is tempting to believe that it will turn out to be foldable in nature. However, new OEM teasers show that it is a traditional slab, albeit one with interesting features such as main cameras that can hide under color-changing glass.
https://www.notebookcheck.net/OnePlus-Concept-One-looks-like-it-s-not-foldable.449139.0.html
A practical purpose for this would be an electronic variable ND. It'd better not be for pure aesthetics because it looks the "teenage racecar" sort of tacky, though typical for the brand's McLaren line, or the collaboration with luxury auto companies in general.