The human immune system serves as our body’s defense against harmful pathogens and cancer by identifying and eliminating abnormal cells. To maintain immune homeostasis several mechanisms are employed, which involve a wide range of proteins, including the Casitas B lymphoma-b (Cbl-b) protein, present in various immune cells. Cbl-b helps modulate immune responses by downregulating the activity of multiple immune cells. This inhibitory effect is significant in cancer development and progression as it promotes an immunosuppressive tumor environment.