PDCD1 and neoplasm: In 2021, the National Comprehensive Cancer Network (NCCN) and, in 2022, the American Society of Clinical Oncology (ASCO) released a series of recommendation statements and guidelines addressing PD-L1 immunohistochemistry testing, use of combined positive score (CPS), tumor mutational burden (TMB) testing, and PD-1 inhibitor monotherapy and combination therapy in platinum-naïve and refractory patients [41,49].