Fig. 3From: Differences in tumor microenvironments between primary lung tumors and brain metastases in lung cancer patients: therapeutic implications for immune checkpoint inhibitorsRepresentative immunohistochemical images of PD-1, PD-L1, and CD8 in primary lung cancer and brain metastatic tissues of a patient from cohort 2 (patient ID 17). Abbreviations: PD-1, programmed cell death-1; PD-L1, programmed cell death ligand-1Back to article page