Further studies in this regard—e.g., aimed at evaluating PDL-1/PD-1 modulation in COVID-19 patients—might be desirable in order to clarify this important issue and to gain insight into why in COVID-19 patients with an altered immune response the occurrence of hypoxia and inflammation (also present in other diseases such as severe influenza) leads to an undesirable outcome. This evidence concerns the gene CD274 and COVID-19.