Both Fujifilm X-T10 and Panasonic GX85 have 16.0 MP resolution sensors but Fujifilm X-T10's sensor is APS-C (23.6 x 15.6 mm ) and Panasonic GX85's sensor is Four Thirds (17.3 x 13 mm ).
Since Fujifilm X-T10'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 Panasonic GX85.
Below you can see the X-T10 and GX85 sensor size comparison.
As seen above, Fujifilm X-T10 has a 1.6x Larger sensor area than Panasonic GX85. 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.