Below you can see the front-view size comparison of the Fujifilm X-Pro2 and Fujifilm GFX 50R. The Fujifilm X-Pro2 is clearly the smaller of the two cameras. Its body is 20mm narrower, 14 mm shorter and 10 mm thinner than the Fujifilm GFX 50R.
The chart below depicts how two cameras compare with average dimensions of the cameras in their class.