The STAT3 pathway plays a critical role in cardiac fibrosis by regulating CF phenotype and activation, studies show that C188‐9 inhibition of STAT3 phosphorylation suppresses skin fibrosis [18, 25], and we tested whether C188‐9 inhibited cardiac fibrosis via STAT3, analyzing ISO‐induced mouse hearts with or without C188‐9 treatment. Here, STAT3 is linked to cystic fibrosis.