Verizon has a security feature built around this, https://www.xfinity.com/hub/smart-home/wifi-motion
Philips WiZ bulbs: https://www.wizconnected.com/en-us/explore-wiz/spacesense
Alarm.com also supports such sensors: https://poweredbyalarm.com/eventresources/wp-content/uploads...
There's a big difference between 'presence detection' and 'tracking individuals'. Both in terms of tech and privacy impact.