Distribution of immune checkpoint in tumor cells and immune microenvironment. CTLA-4, cytotoxic T lymphocyte antigen-4; MHC, major histocompatibility complex; PD-1/PD-2, programmed cell death-1/-2; PD-LI/PD-L2, programmed cell death receptor-1/-2 ligand; TCR, T cell receptor. Distribution of immune checkpoint in tumor cells and immune microenvironment. CTLA-4, cytotoxic T lymphocyte antigen-4; MHC, major histocompatibility complex; PD-1/PD-2, programmed cell death-1/-2; PD-LI/PD-L2, programmed cell death receptor-1/-2 ligand; TCR, T cell receptor. Tanvir F. Kabir et al. TOJ 2018;18:370-376 Copyright © 2018 by Ochsner Clinic Foundation