Ok the colors in the BG dont fit with the cut/render.
Maybe take a nice Stock for the BG and blur it.
Then make a gradient map to align the cut with the BG.
Maybe take a C4D and bring some parts of it in the BG and blur it and smaler parts of the same C4D in the front of the cut and sharpen them.
Look at the Cut/Render where the Light is coming from...put there with a soft, round, white Brush a light source and darken the other side.

Greets
BAB