Yes. On the Canon 7D Mark II, exposure compensation can be used in Manual mode when Auto ISO is enabled.

In this mode, shutter speed and aperture stay fixed because you chose them manually; exposure compensation shifts the Auto ISO target instead. So the camera won’t change your shutter or aperture values, but it should raise or lower ISO to make the image brighter or darker, as long as the needed ISO is within the camera’s available range.

A common way to access it is to assign the Set button to Exposure Compensation via the camera’s custom controls/functions. Once configured, you can dial in positive or negative compensation while staying in Manual + Auto ISO.

Also, don’t rely only on the manual-mode meter display. The key test is the actual result: if compensation is working, the camera should choose a different ISO and the image/histogram should shift accordingly.