CRP and melanoma: At present, proposed host peripheral biomarkers of response to ICI in melanoma include pre-treatment and early on-treatment changes in circulating immune cells composition,11, 12, 13 pre-treatment serum levels of lactate dehydrogenase (LDH),14soluble forms of CTLA-4,15 PD-1, and PD-L1,16 as well as inflammatory proteins17,18 (i.e., C-reactive protein (CRP) and interleukins).