Knockout of ATF4 inhibited ferroptosis inducer‐mediated mitophagy and enhanced erastin‐ or RSL3‐ or cystine deprivation‐induced ferroptosis and lipid peroxidation in cancer cells, and the overexpression of Parkin strongly reversed the effect of ATF4 knockout on cancer cells (Figure S4A–J, Supporting Information). Here, ATF4 is linked to cancer.