PDCD1 and neoplasm: Transcriptomic analysis of tumor-infiltrating leukocytes showed that systemic p38 blockade with p38i and tumor-specific p38α inactivation decreased expression of exhaustion-associated transcripts (i.e., Lag3, Ctla4, Pdcd1, Lgals3, Pdcd1lg2, and Havcr2) in T cell populations, defined by expression of the T cell markers (Fig. 2b–c).