For example, an unsupervised machine learning algorithm (Hierarchical Clustering) was used to cluster hospitalized COVID-19 patients in to three categories merely based on 12-plex cytokine panel (IL-1 β, IL-6, IL-8, IL-10, IL-17, TNF, IFN-α, IFN-γ, CXCL10, CCL2, CCL3, G-CSF), and significant differences in mortality rates were found among the clusters (Castro-Castro et al., 2022). This evidence concerns the gene CXCL8 and COVID-19.