Hospitalized patients with severe COVID-19 exhibit high serum levels of type I IFN (IFN-I; IFN-α and IFN-β), type II IFN (IFN-II; IFN-γ), IL-2, IL-7, IL-10, granulocyte colony–stimulating factor, TNF, C-X-C motif chemokine ligand 10 (CXCL10), monocyte chemoattractant protein 1 (MCP1), and macrophage inflammatory protein (MIP1α) (3–5). Here, CXCL10 is linked to COVID-19.