Both Canon M3 and Leica M Edition 60 have 24.0 MP resolution sensors but Canon M3's sensor is APS-C (22.3 x 14.9 mm ) and Leica M Edition 60's sensor is Full frame (36 x 24 mm ).
Since Leica M Edition 60's has a larger sensor area with the same resolution, this means that it also has a larger pixel area hence better light collecting capacity for a given aperture compared to Canon M3.
Below you can see the M3 and M Edition 60 sensor size comparison.
As seen above, Leica M Edition 60 has a 2.6x Larger sensor area than Canon M3. 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.