PDCD1 and neoplasm: Pembrolizumab, another anti-PD-1, prolongs survival compared with docetaxel as second-line treatment, with at least 1% of tumor cells expressing PD-L1 (24); and as a front line, pembrolizumab has demonstrated improved survival and response compared to platinum-based chemotherapy if ≥50% of tumor cells express PD-L1 (21).