Compared to paclitaxel, pembrolizumab, a programmed cell death 1 (PD-1) inhibitor as a kind of immunotherapy, did not significantly improve OS as second-line therapy for advanced GC with a programmed cell death ligand 1 (PD-L1) combined positive score (CPS) of 1 or higher, although pembrolizumab had a better safety profile [10]. The gene discussed is PDCD1; the disease is gastric cancer.