https://www.cnet.com/news/apple-rear-3d-sensors-for-2019-iphone-report/

The iPhone X uses its own kind of 3D sensing tech.

Apple's already using a 3D sensor in the iPhone X. New features on the iPhone X like Face ID and Animojis owe their existence to the iPhone's TrueDepth camera system, which uses infrared and 3D sensors to create a three dimensional map of your face. This makes Apple's facial recognition more accurate and it's the reason you can't unlock an iPhone X with just a photograph.