Hi @karthik palani ,
If your internet end-user machines still on Internet, you can manage them separately using Intune, easy to deploy.
Co-management will gives you the possibility to co-manage the device using two platform, Configuration Manager when the device is connected internally and Intune externally (Internet), there is some workloads to be configured.
CMG or Cloud Management Gateway has nothing with Intune, It's like a gateway between your ConfigMgr infrastructure and your internet devices, if you are planning to push content (other than software updates) to Internet users, you have to setup a Cloud Distribution Point too.
Regards,
Youssef Saad | New blog: https://youssef-saad.blogspot.com
Please remember to ** “Accept answer” ** for useful answers, thank you!