CD9 and COVID-19: Two cMo subsets (cMo CD11a-CD64- and cMo CD9-HLADRlo had lower expression of the activation markers CD64, CD11a, and CD86 (Figure 2B and Supplementary Figure 2A), suggesting that these are either immature monocyte phenotypes or the newly emigrated monocyte precursors found in COVID-19 (33, 34).