In our study, the expression of PD-L1 is overexpressed in melanoma cells and tissues compared with melanocytes and normal skin tissues, respectively (Figure 2); and the positive correlation between α9-nAChR and PD-L1 expression by using melanoma cell lines, tissue microarrays, and public databases (Figure 2 and Figures S3–S5). Here, CD274 is linked to melanoma.