IL2 and metastatic malignant neoplasm: IL‐2 is a pleiotropic cytokine that plays a critical role in the immune response.[37] High dosage of IL‐2 treatment is one of the first successful immunotherapy to metastatic cancers.[38] We found IL‐2 promotes tumor‐infiltrating CD8+ T‐cell responses in ALTEN preserved tissues, recapitulating the observation from a recent tumor xenograft model.[18] To our knowledge, ALTEN is the first rapid and cost‐effective method to assay the effects of immunomodulators ex vivo in preserved cellular niches.