Immunology is a fascinating field of study that looks into how the body defends itself against infection and disease. It is a complex system that involves both the innate and adaptive immune systems. In this article, we will take a comprehensive look at immunology, exploring how the innate and adaptive immune systems work together to protect us from harm. We will also discuss the different use cases of immunology in modern medicine and its potential implications for future treatments. Finally, we will explore what can be done to better understand this complex system and develop more effective treatments for diseases. It is an interdisciplinary field that involves understanding how the body's innate and adaptive immune system works, and how it interacts with other systems. They may also offer enduring defence. The adaptive immune system, for instance, provides lifelong immunity to measles for those who have recovered from the disease, but not to other common viruses like those that cause mumps or chickenpox. Since adaptive immune responses are the main topic of this chapter, they are what we will refer to as immune responses throughout.