HCQ might also interfere in the cytokine storm caused by COVID-19 through several pathways, such as the inhibition of the presentation of antigen by the antigen-presenting cells to T cells, declining the total of T cells activations, the blockage of TLR-9, activation of TLR-7, interfering in the Stimulator of Interferon Gene (STING) pathway—cyclic guanosine monophosphate–adenosine monophosphate (GMP-AMP) synthase, and ultimately decreasing the production of cytokines [70,81,82,83,84]. Here, TLR9 is linked to COVID-19.