Below you can see the front-view size comparison of the Nikon D7500 and Olympus E-M5 II. The Olympus E-M5 II is clearly the smaller of the two cameras. Its body is 12 mm narrower, 19 mm shorter and 28 mm thinner than the Nikon D7500.
The chart below depicts how two cameras compare with average dimensions of the cameras in their class.