STAT3 and neoplasm: Moreover, ZA restores the doxorubicin-induced immunogenic cell death and reverses the tumor-induced immunosuppression due to the production of kynurenine, by inhibiting the signal transducer and activator of transcription-3 (STAT3)/ indoleamine 2,3 dioxygenase (IDO) axis, which is highly activated in cancer cells.