The levels of histone H3 acetylation in the PD-L1 promoter region (− 1178 bp to − 1117 bp, − 455 bp to − 356 bp, and − 105 bp to − 32 bp from PD-L1 exon 1) of these drug-resistant cancer cells were significantly increased (Fig. 4a). Here, CD274 is linked to cancer.