CD4 and COVID-19: As the known CXCR3 ligands, CXCL9, CXCL10, and CXCL11, are predominantly induced by IFNγ (51), the presence of this CXCR3-expressing CD11b+CD14+ monocyte subset may be mechanistically related to the synchronous increase in the IFNγ-producing CD4+ T cell subset in our convalescent COVID-19 cohort (Figure 2D).