https://www.cnet.com/news/lg-g8-can-unlock-by-scanning-the-veins-in-your-hand/

Hand ID builds into another feature called Air Motion. Because the phone's front camera can track and read your hand movements, you can interface with the phone in a whole new, touchless way.

By pinching your fingers and thumbs together (as if making a bird's beak with your hand and pointing it downward over the phone's camera), you can swipe left and right to launch certain apps, pause or play media and even adjust the volume by miming a twist of a jog dial.