Zeiss ZX1 has a
37.0MP Full frame (36 x 24 mm ) sized CMOS sensor . On the other hand, Leica Q-P has a
24.0MP Full frame (36 x 24 mm ) sized CMOS sensor and features Maestro II processor.
Zeiss ZX1's sensor provides 13MP more than Leica Q-P's sensor, which gives a significant advantage in real life. You can print your images larger or crop more freely.
On the other hand, please keep in mind that Max sensor resolution is not the only determinant of resolving power. Factors such as the optical elements, low pass filter, pixel size and sensor technology also affects the final resolution of the captured image.
Below you can see the ZX1 and Q-P sensor size comparison.
Zeiss ZX1 and Leica Q-P have the same sensor sizes so they will provide same level of control over the depth of field when used with same focal length and aperture. On the other hand, since Leica Q-P has 55% larger pixel area (36.00µm2 vs 23.11µm2) compared to Zeiss ZX1, it has larger pixel area to collect light hence potential to have less noise in low light / High ISO images.