PDCD1 and neoplasm: To date, pembrolizumab, an anti-PD-1 drug, is a standard first-line treatment in advanced NSCLC with high PD-L1 TPS (i.e., positivity in at least ≥50% of tumor cells by IHC in patients without sensitising alterations involving the epidermal growth factor receptor (EGFR) or anaplastic lymphoma kinase (ALK) genes) [23].