Cellular immunology is a branch of immunology that focuses on the study of cells involved in the immune response, particularly T cells, B cells, and macrophages. This field explores how these immune cells interact with pathogens, recognize antigens, and coordinate the body's defense mechanisms against infections and diseases. Cellular immunologists investigate the roles of different types of immune cells in both the innate and adaptive immune responses, as well as how dysregulation of these cells can lead to autoimmune disorders, allergies, and other immune-related conditions. They also study the development and function of immune cells within tissues and organs, and how they communicate with each other to mount effective immune responses. Overall, cellular immunology plays a crucial role in understanding the complexities of the immune system and developing new therapies and interventions to improve human health.