IL6 and neoplasm: Older age is associated with higher levels of systemic inflammation, with increased levels of pro-inflammatory cytokines such as interleukin (IL)-6 and acute-phase proteins such as C-reactive protein (CRP), a phenomenon often called ‘inflammaging’.42 While high levels of IL-6 in the tumour microenvironment are associated with resistance to checkpoint inhibitors,26,43 more research is needed on the implications of inflammaging on outcomes of immunotherapy.32 Finally, age also influences the interaction between the microbiome and immune system.