Similarly, when gemcitabine is used to treat nasopharyngeal carcinoma, it activates NF-κB to upregulate PD-1 in NK cells and PD-L1 in tumor cells; consequently, combining immunotherapeutic agents such as anti-PD-1 antibodies increases NK cell cytotoxicity by inhibiting the PD-L1/PD-1 checkpoint (265). Here, CD274 is linked to nasopharyngeal carcinoma.