CXCR3 and COVID-19: Broadly speaking, when compared with healthy controls, recovered COVID-19 individuals exhibited differences in the populations of innate immune cells, such as natural killer cells, mast cells, and C-X-C motif chemokine receptor 3+ (CXCR3+) macrophages, as well as adaptive immune cells, such as T-helper cells and regulatory T cells ([82], p. 2).