PDCD1 and psoriasis: One we annotated as cytotoxic effector memory cells (CTLem) due to expression of effector molecules including TNFRSF18 and CD96, as well as resident markers CD69 and ITGAE. Interestingly, the second cytotoxic T cell population was quantitatively enriched in the psoriasis vs. normal samples and contained elevated canonical exhaustion markers such as PDCD1 and LAG3. Accordingly, this population was classified as exhausted T cells (CTLex).