Leica TL2 has a 24.0MP APS-C (23.6 x 15.7 mm ) sized CMOS sensor . On the other hand, 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.
One other difference between these two cameras that is worth mentioning is that Fujifilm X-T3's sensor doesn't have an 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 and X-T3 sensor size comparison.
Leica TL2 and Fujifilm X-T3 have almost the same sensor size so none of them has any significant advantage over other in providing control over depth of field when used with same focal length and aperture.