PDCD1 and COVID-19: The efficacy of immune checkpoint inhibitors (ICIs) strongly relies on their capacity of inducing T-cell immune reconstitution.1 T-cell exhaustion is a contributory mechanism underlying the severity of SARS-CoV-2 infection,2 leading on one hand to the investigation of programmed-cell death-1 inhibitors as a therapeutic strategy in severe COVID-19.3 On the other hand, given the pathological immune-mediated mechanisms underlying COVID-19 and the risk of immune-pathology stemming from ICI use, there has been growing concern around the use of ICI in patients with COVID-19 and cancer.4 5