Gilead Sciences built its foundation on antiviral medicine. Its HIV franchise leads the market in both treatment and prevention, producing durable, repeat-prescription revenue, and its drugs cured hepatitis C for millions. Oncology is the second act: the Kite unit manufactures CAR-T cell therapies that reengineer a patient's own immune cells, and a broader pipeline targets blood cancers and solid tumors. Founded in 1987, Gilead pairs this science with substantial cash generation and a meaningful dividend, unusual among biotechs.