Vitamin D has been linked to pulmonary fibrosis in several studies, including the association between vitamin D deficiency and ILD in human subjects (Hagaman et al., 2011), the induction of pulmonary fibrosis through the renin‐angiotensin system due to chronic vitamin D deficiency in mice (Shi et al., 2017), and the mitigation of pulmonary fibrosis via the deactivation of the lung renin‐angiotensin system after vitamin D supplementation in a mouse model of IPF (Chang et al., 2021). Here, REN is linked to vitamin D deficiency.