As reported by Android Police, Chrome OS 80 recently hit the beta channel that includes the new gestures. You can swipe up from the bottom of the screen to go home, drag up and hold to see the Chrome overview screen or swipe from left to right to go back. You can also do a short drag up to bring up the dock.
The gestures appear to work with most apps, but some apps with pop-out menus are currently incompatible. We imagine this will be fixed before the software moves out of beta. Other new features include multiple Android-like quick settings pages, although you can't reorder items in the settings pages yet.
To try out Chrome OS 80 in beta, go to Settings in your Chromebook, select About Chrome OS and Detail build information, then select Change channel and switch to the Beta channel.