IL6 and neoplasm: Increased circulating levels of IL-6 and C-reactive protein (CRP) (whose expression is directly dependent on IL-6 during ICI administration) have been recorded in patients with different tumor types developing a broad range of irAEs, and a synergistic antitumor activity has been demonstrated in mouse models combining ICIs with inhibition of the IL-6 axis (Esfahani et al., 2020a).