CD274 and breast cancer: The iRGD‐PSS@PBAE@JQ1/ORI NPs effectively enhanced tumor targeting due to the tumor‐overexpressed αvβ3 integrin receptors; JQ1 and ORI were released from nanoparticles in response to intracellular pH/GSH and achieved remarkable synergistic anti‐breast cancer efficiency by reversing PD‐L1‐mediated immune tolerance, increasing intracellular ROS production, and inhibiting lactic acid secretion.[111] Malignant tumors are usually associated with overexpression of HDAC.