Canon 90D has a
33.0MP APS-C (22.3 x 14.9 mm ) sized CMOS sensor and features DIGIC 8 processor. On the other hand, Samsung NX10 has a
15.0MP APS-C (23.4 x 15.6 mm ) sized CMOS sensor and features DRIM Engine processor.
Canon 90D's sensor provides 18MP more than Samsung NX10'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 90D and NX10 sensor size comparison.
Canon 90D and Samsung NX10 have almost the same sensor size, so neither of them has any significant advantage over the other in terms of providing control over depth of field when used with the same focal length and aperture.