I cannot get the Face ID to work on my iPad Pro. It stopped working a few weeks ago.

While the link refers to iPhone, it is equally applicable to iPad.

To reiterate, if you unable to resolve a problem, you would be well advised to seek assistance directly from Apple Support:

Official Apple Support

You might also visit the Genius Bar at your local Apple Store or Apple Authorised Service Provider (AASP) - where the technicians will be able to test and assess your device. If a fault is confirmed, you'll be in the best possible place to explore your available options:

Genius Bar Reservation and Apple Support Options - Apple

The FaceID camera array is reliant upon several components - including an IR camera and IR dot-projector. If any element of the array is faulty, FaceID will not work.

This iPhone User Guide describes setup and use of FaceID on supported models of iPhone:

Set up Face ID on iPhone - Apple Support

If FaceID has been disabled, you’ll need to follow this guidance:

If an alert says Face ID has been disabled on your iPhone or iPad Pro - Apple Support

If you unable to resolve a problem, you would be well advised to seek assistance directly from Apple Support:

Official Apple Support

You might also visit the Genius Bar at your local Apple Store or Apple Authorised Service Provider (AASP) - where the technicians will be able to test and assess your device. If a fault is confirmed, you'll be in the best possible place to explore your available options:

Genius Bar Reservation and Apple Support Options - Apple