Previous studies showed an association between single nucleotide gene variants (SNVs) of PD-1 and cancer susceptibility. We analyzed PD1.5 C > T and PD1.7 T > C SNVs to investigate their association with the risk of developing metastatic melanoma (MM). Utilizing a cohort of 125 MM patients treated with anti-PD-1 agents and 84 healthy controls, we examined genotype/allele frequencies through a modified Poisson regression model, adjusted for age and sex. Our findings indicate that the PD1.5 T allele is associated with a reduced risk of MM, showing a significantly lower risk in both codominant (RR = 0.56, 95%CL: 0.37-0.87) and dominant (RR = 0.73 95%CL: 0.59-0.90) models. Conversely, the PD1.7 C allele is linked to an increased risk of MM, with the C/C genotype exhibiting a higher risk in the codominant (RR = 1.65, 95%CL: 1.32-2.05) and allelic (RR = 1.23, 95%CL: 1.06-1.43) models. These results are consistent with previous meta-analyses on other cancer types, mainly highlighting the PD1.5 SNV's potential role in promoting anti-tumor immunity through increased PD1-positive circulating effector T cell activity.