PDCD1 and neoplasm: In contrast, CD8T_GNLY+ cells from tumor samples upregulated exhaustion markers (LAG3, KLRG1, PDCD1, HAVCR2) and showed enrichment in pathways that shifted from antiviral responses to immunosuppression and signal regulation programs, including PD-L1/PD-1 checkpoints, TNF, MAPK, and HIF-1 signaling pathways (Figures 3D, E).