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. Here, KRT17 is linked to pulmonary fibrosis.