CD274 and melanoma: Besides the above transcription factors, recent work have verified nuclear factor E2-related transcription factor 2 (NRF2) as an upstream transcriptional activator of PD-L1 in human primary keratinocytes and melanocytes after ultraviolet-B irradiation, and depletion of NRF2 significantly increases T cells infiltration in the tumors and suppresses melanoma progression (234).