Leica Q2 has a 47.0MP Full frame (36 x 24 mm ) sized CMOS sensor . On the other hand, Zeiss ZX1 has a 37.0MP Full frame (36 x 24 mm ) sized CMOS sensor . Leica Q2's sensor provides 10MP more than Zeiss ZX1'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.
Another difference between these two cameras is that Leica Q2's sensor lacks anti-alias (Low-Pass) filter. Removing anti-alias filter increases the sharpness and level of detail but at the same time, it increases the chance of moire occurring in certain scenes.
Below you can see the Q2 and ZX1 sensor size comparison.
Leica Q2 and Zeiss ZX1 have 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 Zeiss ZX1 has 24% larger pixel area (23.11µm2 vs 18.49µm2) compared to Leica Q2, it has larger pixel area to collect light hence potential to have less noise in low light / High ISO images.