Nikon D500 has a
21.0MP APS-C (23.5 x 15.7 mm ) sized CMOS sensor and features Expeed 5 processor. On the other hand, Leica M Edition 60 has a
24.0MP Full frame (36 x 24 mm ) sized CMOS sensor .
Another difference between these two cameras is that Nikon D500's sensor lacks anti-alias (Low-Pass) filter. Removing anti-alias filter increases the sharpness and level of detail but at the same time, it increases the chance of moiré occurring in certain scenes.
Below you can see the D500 and M Edition 60 sensor size comparison.
As seen above, Leica M Edition 60 has a 2.3x Larger sensor area than Nikon D500. Larger sensors give photographer more control on the depth of field and blurry background compared to smaller sensor when shot in same focal length and aperture.