ObjectiveTo investigate the reversal effect of Cordyceps sinensis extract on immunotherapy resistance of non-small cell lung cancer （NSCLC）. MethodsELISA， flow cytometry， and co-culture assays were performed to evaluate the effects of Cordyceps sinensis extract on cytokine secretion， proliferation， and tumor cell killing activity of Jurkat （JKT） cells. Furthermore， the therapeutic effect of Cordyceps sinensis extract on programmed cell death ligand 1 （PD-L1） resistant lung cancer was evaluated through in vivo experiments both alone and in combination with anti-PD-L1 monoclonal antibody. ResultsCordyceps sinensis extract enhanced the secretion of cytokines interferon gamma（IFN-γ）， tumor necrosis factor-alpha（TNF-α） and interleukin-2 （IL-2）in JKT cells， promoted cell proliferation （P=0.006）， and boosted their killing function against tumors （P＜0.001）. Compared with the control group， in vivo study demonstrated that Cordyceps sinensis extract monotherapy effectively inhibited the growth of PD-L1-resistant tumors ［tumor growth inhibition value （TGI）=26.1%， P=0.090］， while its combination with anti-PD-L1 antibody significantly reversed PD-L1 resistance （TGI=50.6%， P＜0.001）. ConclusionThis study provides certain data support for the activation of anti-tumor immunity by Cordyceps sinensis extract， and offers a new treatment strategy for enhancing anti-tumor immunity and reversing immune resistance in lung cancer.