Cancer immunotherapy uses the host′s immune system to mobilize immune cells to rec-ognize and eventually eliminate cancer cells .At present, studies in terms of cancer immunotherapy mainly focus on programmed cell death protein 1/programmed death-ligand 1 (PD-1/PD-L1) antibody, cytotoxic T-lymphocyte-associated protein 4 ( CTLA-4 ) antibody, chimeric antigen receptor T-cell immunotherapy (CAR-T), T cell receptor Immunotherapy (TCR-T), etc.Despite the fact that cancer immunotherapies elicit unprecedented durable responses in clinical therapy , they appear to be ineffective to some patients .In addition, some responders relapse and show resistance to immunotherapies even if their symptoms are re -lieved for a time .Resistance to cancer immunotherapy can be categorized into primary , adaptive and ac-quired, which can occur in every stage during the process of anti-tumor response.In this review, we discuss the known mechanisms of resistance and provide a rationale for the use of combination therapy to overcome resistance.

OBJECTIVE To investigate the changes in high performance liquid chromatography （HPLC） fingerprint spectra and nucleoside components between Pinelliae Rhizoma Praeparatum cum Zingibere et Alumine and its processed product Succus bambusae pinella preparata， providing a reference for the quality evaluation of the latter. METHODS HPLC fingerprint was established for 10 batches of Pinelliae Rhizoma Praeparatum cum Zingibere et Alumine and its processed product Succus bambusae pinella preparata following the Similarity Evaluation System of TCM Chromatographic Fingerprints （2012 Edition）. Hierarchical cluster analysis （HCA）， principal component analysis （PCA）， and orthogonal partial least squares-discriminant analysis （OPLS- DA） were conducted on their common peaks. The contents of four nucleoside components， hypoxanthine， uridine， adenine， and guanosine， in both Pinelliae Rhizoma Praeparatum cum Zingibere et Alumine and Succus bambusae pinella preparata were determined. RESULTS The similarity between the fingerprints of the 10 batches of Pinelliae Rhizoma Praeparatum cum Zingibere et Alumine， Succus bambusae pinella preparata， and their corresponding reference fingerprints ranged from 0.851 to 0.990. A total of 10 common peaks were obtained for both samples， and 4 components were identified as hypoxanthine， uridine， adenine， and guanosine. The results of HCA， PCA and OPLS-DA showed that the samples of Pinelliae Rhizoma Praeparatum cum Zingibere et Alumine and Succus bambusae pinella preparata were clustered into separate categories， with OPLS-DA selecting 4 differential components between them， ranked by variable importance projection values as peak 8， peak 1， peak 6 （adenine） and peak 10. The content determination results showed that the average contents of hypoxanthine， uridine， adenine and guanosine in Succus bambusae pinella preparata declined by 15.90%， 12.00%， 26.04% and 22.18% compared to Pinelliae Rhizoma Praeparatum cum Zingibere et Alumine， respectively， with statistically significant differences in the contents of hypoxanthine， adenine and guanosine （P＜0.05 or P＜0.01）. CONCLUSIONS The established fingerprint and content determination methods are simple to operate and have good repeatability， which are suitable for qualitative and quantitative analysis of Pinelliae Rhizoma Praeparatum cum Zingibere et Alumine and Succus bambusae pinella preparata. The average contents of the four nucleoside components decreased after the processing of Succus bambusae pinella preparata.