Both Fujifilm X100F and Panasonic S5 II have 24.0 MP resolution sensors but Fujifilm X100F's sensor is APS-C (23.6 x 15.6 mm ) and Panasonic S5 II's sensor is Full frame (35.6 x 23.8 mm ).
Since Panasonic S5 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 Fujifilm X100F.
Another similarity between these two cameras is that both Panasonic S5 II and Fujifilm X100F sensors lack anti-alias (Low-Pass) filters. 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 X100F and S5 Mark II sensor size comparison.
As seen above, Panasonic S5 II has a 2.3x Larger sensor area than Fujifilm X100F. 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.