Joe does Zoom with his friends, but he can't see his video. Leo says to check the video settings and make sure it has the right camera selected. Make sure the camera is turned on and any shutters are open. Some webcams have one on the lid for privacy. Also, look in the settings to make sure your camera is actually enabled. The camera may be turned off as a security feature. Double-check in another camera app to see if it works to be sure.
From the chatroom - There's a tech note here, on why Lenovo cameras don't work in Zoom. It's likely a privacy feature that needs to be disabled.