Importantly, further in the ICI response monitoring setting, ctDNA BRAF, NRAS and KIT mutations were analyzed using ddPCR in melanoma patients with active brain metastases receiving anti-PD-1-based therapy, with longitudinal ctDNA plasma samples over the first 12 weeks of treatment (threshold 2.5 copies/mL plasma) [99]. This evidence concerns the gene NRAS and melanoma.