Perhaps add a sun, now there is something off. There are no shades near the houses, yet there are sharp shades from the trees in the foreground.
Look at your materials, for example the car. This looks to some metal kind of material, which looks a bit fake. Or some gangsta rapper is riding those wheels
Lighten the image a bit, but dont lighten sky. Perhaps do a sky replace, this one is burned out and lacks details. Looks weird when bottom part of image is dark and sort of colorless.
You seem to have mixed 2d and 3d people, make sure the lighting is correct on the 2d people. The old guy has light comingfrom his left side (right side of image), yet in the render the sun comes from back left.
Hope this helps a bit