In this study, we leveraged several independent methodologies, including qRT-PCR, immunoblotting, IP, and FACS using distinct primer sets, ab clones, rPD-L1, WT and PD-1 transgenic negative and positive control cell variants, to validate PD-1 functional expression by live B16-F10 and YUMM murine melanoma cells. Here, PDCD1 is linked to melanoma.