PDCD1 and lung cancer: 18. In terms of immunotherapy, HSP90α was reported to be a potential prognostic biomarker for ICIs combination therapy in hepatocellular carcinoma recently. In addition, high plasma HSP90α was an adverse independent prognostic predictor in lung cancer patients accepting PD-1/PD-L1 inhibitors combination chemotherapy 19. Besides, numerous HSP90 inhibitors with different mechanisms of action have been developed for clinical evaluation with promising results 9,20.