Several peripheral blood indexes, including T cells (CD4+ and CD8+ T lymphocytes) and systemic inflammation (neutrophil-to-lymphocyte ratio (NLR), absolute neutrophil count (ANC), C-reactive protein (CRP), and lactate dehydrogenase (LDH)), have been associated with response or survival outcomes in patients with melanoma and non-small cell lung cancer (NSCLC) receiving immune checkpoint inhibitors (ICIs) (10–15). Here, CD8A is linked to melanoma.