No-one in your video-conference session can see what you're doing with your own screen, right? Wrong, say a team of cybersecurity researchers. They have developed a new system, Synesthesia, to convert audio from your mic into the website you're looking at.
https://www.notebookcheck.net/Security-researchers-demonstrate-how-to-spy-on-screens-during-video-calls.327214.0.html