https://www.androidpolice.com/google-pixel-4-killed-motion-s...

> Regulatory issues were likely a major factor that led to the demise of Soli and Motion Sense on future Pixel models. Soli operates in the 60GHz frequency, which is reserved for military and government use in India.. Many of the Google Pixel 4's Motion Sense gestures are available.. Nest Hub's Soli radar extends far enough to detect when you're sleeping, and to track your breathing.