Navigation gestures are now a thing on Android Pie. See that pill-shaped button at the bottom of the screen? That replaces the three buttons that previously were used on Android.
The feature is optional, and off by default. You can enable it by going to Settings > Gestures> Swipe up on Home Screen and toggling the switch.
Of course, different phone makers will have different interpretations of how gestures should work on Android Pie.
For example, Google’s Pixel 3 and Pixel 3 XL are all-in on gestures and lack an option to disable them. Samsung, on the other hand, has a unique approach to gestures in its One UI beta.