I have a MacBook Pro 2016 (with Touch Bar), yesterday I installed Snap Camera (by Snapchat) and it worked while I was on a video call. Afterwards, when the call had ended the green camera light got stuck on.
I force quit all apps but it stayed on, I then restarted the Mac and the light persisted through the whole reboot. So I then shutdown the Mac and it turned off.
Since then, camera has not worked. I reset the SMC, PRAM and am currently waiting for macOS to reinstall (didn't wipe data).
It sounds like there is a hardware issue to me, but just seems like a funny coincidence that it occurred immediately after finishing a video call where I had just used Snap Camera for the first time.
My Apple Care has now expired, so guess I'm out of luck? Anything else I can try?