Lastly, we also observed in the Severe-Death group an IL-15-based axis characterized by both strong positive and negative correlations with several immune mediators (Figure 7C), which highlights the need of a thorough investigation about the role of IL-15 in patients with cancer and COVID-19, given that exhausted T and NK cell populations are observed throughout the disease (17, 28, 35). The gene discussed is IL15; the disease is COVID-19.