PD-1/PD-L1 engagement has been observed in various cancer types, while the expression of PD-L1 is used to predict the response of patients to anti-PD-1/PD-L1 treatment.41 The regulation of PD-L1 has been studied in different aspects, including genomic, epigenetic, transcriptional or post-transcriptional regulation and modification.42 It is reported that PD-L1 expression is regulated by oncogenic genes, such as JAK2V617F. Here, PDCD1 is linked to cancer.