image courtesy of imaging-resource
Imaging-Resource published an extensive ISO comparison that includes the Nikon D500, Fujifilm X-T2, and more against the Olympus OM-D E-M1 Mark II. Surprisingly, the camera does very well, except in the reds. You can see the comparison here. They also posted their M.Zuiko ED 25 f/1.2 Pro review here.
Olympus OM-D E-M1 Mark II Pre-order Amazon/B&H Photo/Adorama
Olympus M.Zuiko Digital ED 25mm f/1.2 PRO Amazon/B&H Photo/Adorama