Start with checking the physical switch that covers the webcam, if there is one. Some laptops (especially Lenovo's) have a privacy switch that turns the webcam on or off on the hardware level.

As expected, Lenovo has unveiled the first laptop with an under-display camera that’s invisible to the eye when not in use. The new Lenovo Yoga Slim 9i is a laptop with a 14 inch, 3840 x 2400 ...