Video Explainer: What’s going on in Xinjiang?

The Grand Bazaar in Urumqi, capital of Northwest China's Xinjiang Uygur Autonomous Region

In this video here, Carlos Martinez goes into detail about the situation in Xinjiang.

What are the accusations being made?
Who is making the accusations?
What’s the state of the evidence?
What reasons would the Western media and political class have for making so much noise about Xinjiang?