IL6 and Cowden syndrome 1: We have already shown that the activation of the IL-6/Th1 axis is an indicator of severe CS-refractory irAEs, such as ICI-related myocarditis,2 hemophagocytic lymphohistiocytosis25 and cholangiohepatitis,24 which could suggest that the IL-6/Th1 axis may be a possible common blood biomarker for CS-refractory irAEs.