CXCL13 and neoplasm: Remarkably, EV‐loaded protein hydrogels have been shown to induce the de novo formation of tumor‐localized tertiary lymphoid structures, even in the absence of genetic modification, using only spleen‐derived EVs.[307] This approach transcends conventional immune activation by inducing spatially organized immune microenvironments—characterized by CXCL13+ stromal networks and PNAd+ high endothelial venules—that support structured and sustained antitumor immunity.