By and large, worn with a dinner suit, a cummerbund is a belt of cloth, frequently silk worn around the waist. It is worn in modern times for looks only and was first used by high level Officers of the British Army serving duty in India.
Your skill, experience and intelligence is what gets you ahead in business. Of this there can be no denying. However, it’s often how you are “perceived” that counts almost as much. The way people think of you affects how they view you as a businessman and they will often follow their first impressions. How can a nice business tuxedo work to your advantage?