There is also evidence that critically ill COVID‐19 patients, as measured based on PaO2/FiO2 ratio (<200) (8, 9), display higher plasmatic levels of chemokines (CXCL8, CXCL9, CXCL10), cytokines (IL-6, IL-10), and reactive oxygen species (ROS), bringing attention to the role of the host immune system in developing infection-related complications (10, 11). The gene discussed is CXCL9; the disease is COVID-19.