Hey,
I have come across a relatively recent development in motion and presence sensing industry. STHS34PF80. This is a new type of sensor that’s different from PIR & mmwave solutions. In particular both mmwave & PIR sensors can only sense motion (though in different ways), so heuristics and timers are utilized to determine whether there is a presence of a person in an area. Heuristics like these have a couple of issues however: they stay positive for some configured time even after the person has left the area, and sometimes there are situations where the presence channel turns off prematurely because the person neglected to move enough to trigger a motion detection.
Well, this TMOS sensor supposedly works more like a camera in an infrared spectrum so it is able to determine whether there’s something warm (like a person) in its field of view or not. That allows it to detect not just motion but also presence without resorting to heuristics. This would mean that the lights can turn off pretty much right as the person is leaving the area and it would spell the end to people waving at their PIR sensors because the lights turned off at a bad time 
One downside of this particular product (which is the only implementation of the TMOS idea that I am aware of currently) is its relatively limited detection range: 2-4 meters (without lenses – adding lenses allows trading off FOV angle for more range). That would mean it would be limited to a ceiling sensor?
Relevant presentation
Relevant video:
