What are benifits of doing MS in US if someone want to work in India (IT sector)?

It really starts with your interests.  If you want to do some cutting edge research in machine learning, or text analytics, a MS can allow you to do that.  You can also use a MS to improve skills and knowledge in a specialized area.  In some cases people may do a MS to be able to apply for jobs in the US. It might be worth finding people whose career path you would like to emulate.  Try talking to such people to understand what they do.  This should help you figure out what you want. You may be able to do the same in Amazon in India.  Follow the same process, find role models, understand what they do, talk to them and figure out how you can do the same.