PDCD1 and neoplasm: In a new analysis of gene expression data previously published by our group, we found that cDC1s in patients with MDS show significantly decreased expression of CD80 and CXCL9. Decreased expression of CXCL9 may be especially important as expression of this chemokine by cDC1s in the tumor microenvironment is necessary for successful anti–PD-1 therapy.46