PDCD1 and acral lentiginous melanoma: In terms of subtype analysis, although the efficacy of the PD-1 inhibitor on acral melanoma patients was marginally significant (p = 0.05) as compared to the conventional therapy group (IFN+OBS), we still reached a non-statistically significant result, wehile the non-significance among the three groups in DMFS could be caused by the inherently poor outcome of PD-1 inhibitors in BRAF-mutant metastatic melanoma patients in real-world clinical practice [36].