CD4 and neoplasm: Meanwhile, PEG2000‐SiNcTI‐Ph/CpG‐ZIF‐8@CM‐based tumor environment‐activated PDT could reshape the immune environment in CT26 tumor‐bearing mice by promoting the repolarization of macrophage toward M1 type, increasing intratumoral infiltration of CD4+/CD8+ T cells, and facilitating the secretion of immunostimulatory cytokines to benefit the photodynamic immunotherapy process.