Correlation analyses were further performed to investigate the potential correlations established in blood samples of melanoma patients during Nivolumab therapy between the levels of immune cell subpopulations (CD3+, CD4+, CD8+, CD19+, CD16+CD56+), assessed by flow cytometry, and the systemic inflammatory markers (SII, SIRI, NLR, MLR, PLR). The gene discussed is CD19; the disease is melanoma.