CD274 and cancer: Herein, a multifunctional “drug‐like” copolymer with the auto‐changeable upper critical solution temperature (UCST), named poly(acrylonitrile‐co‐acrylamide‐co‐N‐(2‐(2‐nitro‐1H‐imidazol‐1‐yl)ethyl)acrylamide (PAAN), was synthesized and exploited to prepare nanoparticles (NPs) for delivering BMS202 (an antagonist of PD‐1/PD‐L1 interaction) and facilitate the depletion of NADPH in cancer cells, which was beneficial for LDRT to regulate the immunometabolism of TME and reinforce the anti‐PD‐L1 therapy against TNBC (Figure 1).