Your cam preview gets replaced by the background preview you clicked.
Click on the “ Virtual Backgrounds” tab if not already selected, then tap on each background to view it. Keep in mind, though, that you’ll need to have at least Windows 7 or Mac OS 10.9. Zoom apps for Windows and macOS look and function in the same way. Once you’ve enabled virtual backgrounds on your account, you can move on to using the Zoom app to tweak your virtual background settings. To be safe and before using the app, ensure that the virtual background option is enabled. By default, your account settings should have the virtual backgrounds option enabled.