Does Surface Pro 4 support Windows Hello Facial Recognition?

Yes, the Surface Pro 4 supports Windows Hello facial recognition via its integrated IR camera.

Windows Hello Face Authentication uses an infrared camera to map your unique facial features and sign you into Windows 10 quickly, easily and securely.

All Surface Pro 4 models include a built-in IR camera alongside the front-facing webcam. That hardware enables Windows Hello facial unlock so you can breeze past passwords with just a glance.