IL6 and melanoma: Studies in melanoma have found a number of markers that are associated with response to ipilimumab, including expression of genes associated with antigen presentation [38], the T-cell receptor repertoire [39], HLA-I heterozygosity [40], tumour mutational burden [39], somatic copy number mutation burden [41]; systemic immune response factors such as serum IL-6 levels [42]; and gut microbiome variants [43].