CD4 and melanoma: Comprehensive analyses of scRNA-Seq datasets have highlighted novel signatures that were positively correlated with ICI resistance in melanoma [254] while T-cell receptor clonality and TCR profiling, in melanoma patients, have shown greater diversification of pre-treatment circulating CD4+ or CD8+T-cell repertoires and were favorably correlated with longer survival times than patients with lower clone numbers [255,256].