Huawei's patents show two designs with fully exposed displays on the back, which eliminates the need for front cams, as users can easily turn the phone and take selfies. One of the designs comes with a sliding screen that extends by 30%, while the other design's screen can extend by up to 50%.
https://www.notebookcheck.net/New-patents-reveal-that-Huawei-could-soon-release-smartphones-with-slide-out-screens.461833.0.html