https://www.cnet.com/news/the-eye-tracking-htc-vive-pro-eye-is-a-sign-of-vr-to-come/

The Vive Pro Eye is aiming for enterprise markets (which makes sense, since the Vive Pro Eye is expected to cost more than $799 for the headset alone), and Tobii's already built analytics tools using eye tracking to help examine how people interact with advertisements or store layouts. It sounds like eye tracking will largely be a tool used to study engagement, improve graphics and also help improve controls (if I can look at something and then move my hand to control that one thing, it will massively improve aiming).

Qualcomm's next-generation mobile VR headsets are expected to have eye tracking. Mixed-reality headsets like the Magic Leap One and possibly the next-gen Microsoft HoloLens will include it. And in the next few years, every VR and AR headset in existence will probably have it, too.