CD274 and cancer: Recently, we developed self‐assembled DNA nanospheres (NS) as smart delivery vehicles for precise bioimaging and cancer treatment, due to their high biostability, cell permeability, luge loading capacity, and programmable self–assembly and disassembly behaviors.[15] Here, we design a smart self‐assembled NS that can sequentially activate photosensitizers and release PD‐L1 siRNA for efficient synergistic therapy of tumors while reducing side effects on normal tissues.