Panasonic ZS100 has a 20.0MP 1" (13.2 x 8.8 mm ) sized MOS sensor and features Venus Engine processor. On the other hand, Panasonic LX100 II has a 17.0MP Four Thirds (17.3 x 13 mm ) sized CMOS sensor and features Venus Engine processor.
Below you can see the ZS100 and LX100 II sensor size comparison.
As seen above, Panasonic LX100 II has a 1.9x Larger sensor area than Panasonic ZS100. 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.