Scenario:
**I have created a Unity app with a 3D object Cube.
**Build this app with target as iOS and loaded this in an Xcode app with “background blue color with few buttons”.
**On running, I wanted to display only the 3D cube from Unity app (without the default background) along with Xcode blue background. Unity default background should be transparent.
This question has nothing to do with the Unity Hub.
I don’t think any variant of Unity supports a live borderless alpha rendering path, but you can supply whatever image you want to use for a background, if you have some sort of native hooks to get the screen contents before Unity’s window opens.