Janus kinases (JAKs) are a family of enzymes that play a crucial role in cell signaling. They help transmit signals from various cytokines and growth factors to the cell's nucleus, influencing processes like immune response, cell growth, and differentiation. JAKs are essential for the function of several immune system components, making them important in maintaining overall health. There are four main types of JAKs: JAK1, JAK2, JAK3, and TYK2. Each type has specific roles in different signaling pathways. Abnormal JAK activity is linked to various diseases, including certain types of cancer and autoimmune disorders, leading to the development of targeted therapies that inhibit JAK function.