In addition, it has been reported that, of nine melanoma patients treated with anti-PD-1 antibodies who showed pseudoprogression (defined as a tumor size increase prior to response often seen in ICI treatment), all patients had a favorable ctDNA profile defined by undetectable ctDNA at baseline or detactable ctDNA at baseline followed by >10-fold decreases (61). This evidence concerns the gene PDCD1 and melanoma.