In order to use  CADMep you must first have Autocad installed as it is not a stand alone piece of software but more like a plug in for Autocad that has a lot of the functions of Cam duct and ESTmep

I have Autocad and Autocad MEP installed so not sure which 1 CADmep actually needs to run

Autodesk AEC collection has them all including Revit but does not have Cam duct or estMEP included