Both Fujifilm X-A3 and Canon M100 have 24.0 MP resolution sensors but Fujifilm X-A3's sensor is APS-C (23.5 x 15.7 mm ) and Canon M100's sensor is APS-C (22.3 x 14.9 mm ).
Since Fujifilm X-A3'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 M100.
Below you can see the X-A3 and M100 sensor size comparison.
As seen above, Fujifilm X-A3 has a 1.1x Larger sensor area than Canon M100. 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.