Single-cell RNA sequencing (scRNA-seq) analyses of human and murine models of pulmonary fibrosis have uncovered multiple novel cell states involved in lung repair and regeneration, including an intermediate epithelial cell state identified as the KRT5-/KRT17+ aberrant basaloid cells in humans and the cytokeratin 8-positive alveolar differentiation intermediate (Krt8+ ADI) in mice. The gene discussed is KRT5; the disease is pulmonary fibrosis.