CD274 and cancer: Immune checkpoint inhibitors such as programmed death 1 (PD‐1)/programmed death‐ligand 1 (PD‐L1) inhibitors have been applied in a variety of solid tumors, like melanoma, lung cancer, renal cell carcinoma, head and neck squamous cell carcinoma, urothelial carcinoma, esophageal carcinoma, and other tumors, and regarded as the most promising treatment for malignant tumors.2, 3, 4, 5