CXCL9 and COVID-19: The results provide the basis of a model of severe lung tissue damage in COVID-19 in which IFN-γ production by CD8+ T and NK cells (a) activates macrophages and other innate immune cells and (b) induces expression of CXCL9/10/11 (15, 33), promoting further recruitment of CXCR3+ immune cells (including NK and cytotoxic T cells) into lymphoid-rich areas (Figure 6).