Both Pentax W80 and Sony A7S II have 12.0 MP resolution sensors but Pentax W80's sensor is 1/2.3-inch (6.08 x 4.56 mm ) and Sony A7S II's sensor is Full frame (35.6 x 23.8 mm ).
Since Sony A7S II'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 Pentax W80.
Below you can see the W80 and A7S II sensor size comparison.
As seen above, Sony A7S II has a 30.6x Larger sensor area than Pentax W80. 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.