Both Nikon D500 and Nikon D7500 have APS-C sized 21.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
Another similarity between these two cameras is that both Nikon D7500 and Nikon D500 sensors lack anti-alias (Low-Pass) filters. Removing anti-alias filter increases the sharpness and level of detail but at the same time, it increases the chance of moire occurring in certain scenes.
Below you can see the D500 and D7500 sensor size comparison.
Nikon D500 and Nikon D7500 have sensor sizes so they will provide same level of control over the depth of field when used with same focal length and aperture.