There are two approaches for this
- You can use 'dynamic linking" - drag the scene from the ch window into the prem pro window and it will create a dynamic link between them. Updates in ch will be immediately visible in prem pro.
- 'Export the video with "alpha" (transparency) and load this video clip into prem pro - you can then put the background behind it.
I do the second way because dynamic linking can be a bit sluggish (on my little laptop anyway).
You can export with a green screen background and use prem pro to remove it, but i think the quality can suffer a bit - i prefer the export with alpha option.