TCL just showcased its Fold n' Roll tablet from earlier this year (2021) at an event in China. Its screen can fold at the centre and expand into an 10-inch tablet via rollers. The panel is HDR1000 complaint and can dynamically adjust its refresh rate between 48Hz and 240Hz.
https://www.notebookcheck.net/TCL-s-Fold-n-Roll-concept-device-prototype-demonstrated-at-DTC-2021.583262.0.html