IL21 and thyroiditis: found a clonally expanded segment of cytotoxic C‐X‐C motif chemokine receptor 6 (CXCR6)+ CD8+ T cells in thyroid tissue, a population characterised by interferon‐γ (IFN‐γ) and granzyme B upregulation and spurred on by interleukin (IL)‐21, which was indicative of ICI‐induced thyroiditis in NSCLC and other cancer types.97