This is a paid asset, but now you can download Easy Fade Obstruction Free.
Detail this asset from Unity Store: Original Link
Easy Fade Obstruction v1.1
“If possible, please buy the package to support the developer”
Script that allows objects to automatically fade between the Main Camera and the target GameObject(usually a player). Simply pick the layers of objects that you wish to fade, a material with an alpha property, such as the fade or transparent rendering mode available to the standard shader, and you are good to go! It’s a great asset for any fixed-perspective games.