PDCD1 and neoplasm: Consistent with previous studies,1, 2, 18, 19 the transcripts encoding PD‐1 (Pdcd1), Tim‐3 (Havcr2), LAG‐3 (Lag3), CTLA‐4 (Clta4), TIGIT (Tigit), and 2B4 (Cd244) were exclusively expressed by Tex cells of tumor and chronic viral infection as compared to those of the naïve, effector, and memory cells (Figure 1B‐G).