A study of stage IV melanoma patients receiving ICI treatment showed that early disappearance of tumor-associated antigen reactive T- cells (CD4+ T-cells, CD8+-T cells, etc.) from peripheral blood was associated with a better OS (2-year OS: 77.8% vs. 50.6%, HR = 0.25, P = 0.045) and PFS (not reached vs. 3 months, HR = 0.13, P < 0.001) (27). This evidence concerns the gene CD4 and melanoma.