Background: Commonly mutated genes in clear cell renal cell carcinoma include VHL, PBRM1, and BAP1. Although the detection rate of BAP1 mutations in RCC is not high, from an evolutionary perspective. BAP1 mutated renal cell carcinoma tends to have clinical features of higher malignancy, faster disease progression, and poor efficacy of classic drug treatments. Therefore, this study uses our center and TCGA database to analyze the correlation between transcriptome, immune cell infiltration, immune checkpoint expression and other characteristics and the efficacy of immune checkpoint inhibitor-based treatment in patients with BAP1 mutated renal cell carcinoma. Methods: 1. The correlation between the expression of immune-related factors CD4, CD8 and immune checkpoints PD-L1, LAG3 and BAP1 RNA and the expression difference between wild and mutant groups were analyzed through the TCGA database. 2. Collect BAP1 mutant and wild-type patients retrospectively, and verify the expression of CD4, CD8, PD-L1 and LAG3 by immunohistochemistry. 3. The enrichment analysis of the signaling pathway was carried out after the intersection of TCGA and the differential genes of the center. 4. To analyze the clinical curative effect difference between BAP1 wild-type and mutant advanced RCC patients receiving target immunotherapy. Results: The TCGA data confirmed that there was no difference in the expression of PD-L1 RNA between the two groups (P=0.5); while there was a significant difference in the expression of LAG-3 RNA, which was higher in the BAP1 mutant type than in the wild type (P=0.023); 24 cases of BAP1 wild-type ccRCC specimens available in the gene detection database of our center were selected, and the results of immunohistochemistry suggested that there were differences in the expression of LAG3 (p=0.009) between the BAP1 wild-type and mutant types, while PD There was no significant difference in the expression of -L1 (p=0.157). The transcriptome data enrichment analysis results of TCGA and our center database showed that BAP1 was closely related to cytokine signaling, cAMP signaling pathway and immune response signals in the tumor immune microenvironment. In terms of clinical efficacy, the PFS time of BAP1 wild-type RCC patients receiving ICI combined with TKI therapy was significantly longer than that of BAP1 mutant patients (median follow-up time: 23.93 months; median PFS: 24.63 vs. 11.73 months, HR: 0.304, 95%CI: 0.070-1.324, p=0.025). Conclusions: This study found that BAP1 and cytokines, cAMP pathway and immune inflammation-related pathways were significantly enriched at the transcriptome level. IHC results suggested that LAG3 was more highly expressed in patients with BAP1 mutation. Clinical treatment analysis found that PD-1 inhibitor-based immune combination therapy is not effective for patients with BAP1 mutations. In summary, LAG3 may be a potential therapeutic target in the future for patients with BAP1-mutated RCC.