Merck & Co., Inc. develops pharmaceutical products across multiple therapeutic areas, including cardiometabolic disorders, oncology, and infectious diseases. In cancer treatment, its immuno-oncology portfolio, led by Keytruda, represents a significant driver of total revenue. The company also maintains a strong vaccines business focused on preventing pediatric illnesses, alongside Gardasil for human papillomavirus. In addition, Merck markets animal health products. Geographically, 47% of the company’s sales come from its U.S. human health segment, which includes pharmaceuticals and vaccines.