CD274 and neoplasm: Here, we have synthesized multiple functional triblock copolymers comprising a photosensitizer and cationic and thiol side chains and engineered galactose-installed, STING agonist cGAMP and PD-L1 siRNA (siPDL1)–encapsulated polymeric nanoparticles (cGAMP-siPDL1@GalNPs), which synergistically stimulated robust immune responses and inhibited immune evasion by tumor-specific activation of STING, immunogenic cell death (ICD) effects, and silencing PD-L1 expression, for amplified immunotherapy of low immunogenic tumors (Fig. 1, A and B).