Both Panasonic ZS100 and Canon SX710 HS have 20.0 MP resolution sensors but Panasonic ZS100's sensor is 1″ (13.2 x 8.8 mm ) and Canon SX710 HS's sensor is 1/2.3' (6.17 x 4.55 mm ).
Since Panasonic ZS100'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 SX710 HS.
Below you can see the ZS100 and SX710 HS sensor size comparison.
As seen above, Panasonic ZS100 has a 4.1x Larger sensor area than Canon SX710 HS. 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.