Fujifilm X-T3 has a
26.0MP APS-C (23.5 x 15.6 mm ) sized X-Trans CMOS 4 sensor and features X-Processor 4 processor. On the other hand, Canon T7i has a
24.0MP APS-C (22.3 x 14.9 mm ) sized CMOS sensor and features DIGIC 7 processor.
Another difference between these two cameras is that Fujifilm X-T3'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 moiré occurring in certain scenes.
Below you can see the X-T3 and T7i sensor size comparison.
As seen above, Fujifilm X-T3 has a 1.1x Larger sensor area than Canon T7i. 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.