Tumor Necrosis Factor (TNF) is a cytokine, a type of protein involved in the immune system’s regulation and response. Produced primarily by macrophages, TNF plays a key role in inflammation and the body’s defense against infections. It helps to signal immune cells to target and destroy harmful pathogens or abnormal cells, such as cancer cells. However, excessive TNF activity is linked to chronic inflammatory diseases like rheumatoid arthritis, psoriasis, and inflammatory bowel disease. Therapies targeting TNF, such as TNF inhibitors, have been developed to manage these conditions effectively, highlighting its dual role in both protecting and potentially harming the body.