Hello Kunshouling

here's a thought for you: perhaps your global illumination is too bright - or your ambient light is too much. If you think about it, if it's dark enough to have streetlights on, most of the surrounding areas away from the streetlights would be really quite dark - the buildngs would be in silhouette against the skyline and so on.

Maybe it's not a shader problem, but perhaps there is just too much "scene" light, so it's cancelling out the effect of your shaders.