The first Visium study in papillary thyroid carcinoma showed that follicular−like tumour islets localise to well−differentiated peripheries, whereas partial−EMT clusters nestle along invasive edges enriched for cancer−associated fibroblasts; CXCL13+ tertiary lymphoid structures and PD−L1 high tumour foci coexist within millimetres yet display opposing cytokine milieus, validating the “hot−versus−cold” mosaic predicted by dissociated data (34, 35). The gene discussed is CXCL13; the disease is neoplasm.