https://www.cnet.com/news/samsungs-one-ui-which-will-power-the-galaxy-s10-debuts-on-the-s9/

Samsung unveiled the redesigned mobile interface, which runs on top of Google's Android PIe, at its developer conference in November. The goal of One UI is to make interactions natural, even as new phone displays grow larger and take on foldable designs.

The One UI interface is designed to reduce clutter and distractions. Some of the new features include displaying most used functions first and placing buttons within your thumb's reach; allowing the top half of the screen to display content while the bottom half is used to navigate the phone; and improving the visibility of the screen so it's comfortable to stare at longer.