This is a Unity package file, if you download it and import it on your empty Unity project, you will see a demonstration about a camera that follows an object, and this camera (it’s position) is switchable, you can click a button to switch between multiple camera positions and angles. Plus there are two buttons to open two empty scenes, but when you open it the player object and cameras will be there too.
The purpose of this demonstration is to show you how an object like player, camera, etc can be used on multiple scenes without reloading them in each scenes, by adding one line script to make those objects undestroyable when you change scenes.
Here is the download link: https://drive.google.com/open?id=1ksrTMjKqh8y-PQiB_UGhOktbY73Jfk9r