Rare cancers are difficult targets. They have traditionally attracted little attention from researchers, and most have few treatment options. But the advent of targeted therapy and immunotherapy is changing the traditional treatment paradigm to help focus attention on less common cancer types including mesothelioma, biliary tract cancer, and certain types of melanoma. The American Asssociation for Cancer Research (AACR) 2023 Annual Meeting’s second clinical trials plenary session, Hope for Rare Cancers: Novel Targeted and Immunotherapy Agents, highlighted four promising studies that suggest new treatment approaches for rare cancers. The session, which was held Sunday, April 16, can be viewed on the virtual meeting platform by registered Annual Meeting participants through July 19, 2023.