STING1 and neoplasm: Of note, although the immunogenic effects of PARP inhibition create a favorable environment for immunotherapy to work more effectively, PARPi-induced cGAS/STING activation has also been discussed to exert immunosuppressive effects such as upregulation of PD-L1 on tumor cells.3 7 This phenomenon may represent the scientific rationale for the specific susceptibility of PARPi-treated tumor cells to PD-L1 blockade, thereby providing remarkable efficacy by combining these modalities in therapy.