Long non coding RNA(lncRNA)LINC01296 plays a carcinogenic role in different tumor growth,apoptosis,and metastasis,but its mechanism in nasopharyngeal carcinoma is still unclear.The aim of this study is to study the mechanism of knockdown of long non-coding RNA(lncRNA)LINC01296 in inhibiting immune escape of nasopharyngeal carcinoma cells by regulating programmed death ligand-1(PD-L1).In this study,human peripheral blood lymphocytes were isolated and cultured,and then co-cultured with human nasopharyngeal carcinoma cells CNE-2Z,meantime,C57BL/6 mice were injected subcutaneously with CNE-2Z cells to establish a nasopharyngeal carcinoma xenograft model(24 mice).All of them were randomly grouped into control group,lncRNA LINC01296 knockdown group(transfected with lncRNA LINC01296 small interfering RNA(siRNA)),negative control group(transfected with lncRNA LINC01296 siRNA negative control and empty plasmid),and lncRNA LINC01296 knockdown + PD-L1 overexpression group(transfected with lncRNA LINC01296 siRNA and PD-L1 overexpression plasmid).After grouping and transfection,the proportion of activated CD8+ T cells in human peripheral blood lymphocytes was detected by flow cytometry;the killing rate of human peripheral blood lymphocytes to CNE-2Z cells was detected by cell count kit-8 method;the tumor volume of tumor-bearing mice was measured;the CD8 and PD-L1 positive expression in tumor tissue of tumor-bearing mice was measured by immunofluorescence staining;the expression of lncRNA LINC01296 and PD-L1 messenger RNA(mRNA)in CNE-2Z cells and tumor tissues were detected by real-time PCR assay;the expression of PD-L1 protein in CNE-2Z cells and tumor tissues was detected by Western blotting.The results showed that compared with control group,the proportion of activated CD8+ T cells in human peripheral blood lymphocytes,the killing rate of CNE-2Z cells,and the positive proportion of CD8 in tumor tissue of the lncRNA LINC01296 knockdown group increased(P<0.05),the tumor volume and the expression of positive proportion of PD-L1,double positive proportion of CD8 and PD-L1,lncRNA LINC01296,PD-L1 mRNA and protein in CNE-2Z cells and tumor tissue decreased(P<0.05);there was no obvious change in each index of the mice in the negative control group(P>0.05);overexpression of PD-L1 can weaken the effects of lncRNA LINC01296 knocking down on various indicators in CNE-2Z cells and mice.In summary,knockdown of lncRNA LINC01296 can promote the activation and infiltration of CD8+ T cells by down-regulating PD-L1,attenuate the immune escape of nasopharyngeal carcinoma cells,and enhance the lethality of CD8+ T cells.