Merck & Co., Inc. is a prominent global healthcare enterprise. It operates through two core segments: Human Pharmaceuticals and Animal Health. Its Pharmaceutical segment delivers human health products, including medications for critical therapeutic areas such as oncology, hospital acute care, immunology, neuroscience, virology, cardiovascular health, and diabetes. This segment also develops and distributes a comprehensive portfolio of vaccines for pediatric, adolescent, and adult populations. The Animal Health division is dedicated to the research, development, manufacturing, and commercialization of veterinary pharmaceuticals, vaccines, and advanced health management solutions. Furthermore, it offers digitally-enabled products for animal identification, traceability, and monitoring. Merck serves a diverse clientele, encompassing drug wholesalers and retailers, hospitals, government agencies, managed healthcare providers (e.g., health maintenance organizations and pharmacy benefit managers), individual physicians, physician distributors, veterinarians, and animal producers. The company engages in strategic collaborations with entities like AstraZeneca PLC, Bayer AG, Eisai Co., Ltd., Ridgeback Biotherapeutics, and Gilead Sciences, Inc., particularly for the co-development and marketing of long-acting treatments for HIV. Established in 1891, Merck & Co., Inc. maintains its corporate headquarters in Kenilworth, New Jersey.