CTLA4 and cancer: Many investigators have therefore turned to the profiling of inhibitory receptors with a relevant role in TEX biology, such as PD-1 (alone or in combination with other inhibitory receptors such as CTLA-4, Tim-3, Lag-3, 2B4, CD160, TIGIT, and others) for the assessment of exhausted T cells in chronic infections and cancer (20, 25–35).