In coronavirus disease 2019 (COVID‐19), immune cells of bronchoalveolar lavage fluid (BALF) from patients with varying severities of COVID‐19 were profiled by scRNA‐seq and showed that proinflammatory monocyte‐derived macrophages are abundant in patients with severe COVID‐19, while moderate cases are characterized by CD8+ T cells.14 This evidence concerns the gene CD8A and COVID-19.