Researchers have shown that hypoxia induces high expression of KLF4 in different cells, such as human aortic smooth muscle cells (Shan et al., 2020) and pulmonary arteriole smooth muscle cells, in mice with hypoxia‐induced pulmonary hypertension and pulmonary hypertension patients (Sheikh et al., 2015). Here, KLF4 is linked to pulmonary hypertension.