CD274 and melanoma: Immunotherapy has become a major hot topic in oncology treatment research, and inhibitors targeting the PD1-PDL1 axis have been approved as second- or first-line therapies for an increasing number of types of malignancies, including melanoma, lymphoma, lung cancer, renal cell carcinoma, head and neck squamous cell carcinoma, bladder cancer, liver cancer, and gastroesophageal cancer.