MS‐275 is a class I HDAC selective inhibitor that can inhibit the cellular function of HDAC1/2/3 to prevent malignant cancer proliferation.[53] As studies have proven the efficacy of HDAC3 in osimertinib‐resistant lung cancer cells, we chose this drug to investigate its synergistic effect with EGFR degraders. The gene discussed is HDAC9; the disease is lung cancer.