Background <p>The inflammation-immune-nutrition score (IINS) plays a significant role in predicting survival outcomes across various cancers. The study aimed to comprehensively evaluate the prognostic value of IINS in different cancers through a meta-analysis.</p> Methods <p>A systematic literature search was conducted in PubMed, Embase, Web of Science and Scopus databases for eligible studies published up to March 15, 2026. Pooled hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated to assess the associations with overall survival (OS), disease-free survival (DFS), progression-free survival (PFS) and recurrence-free survival (RFS).</p> Results <p>A total of 10 studies from 8 articles encompassing 3979 patients were included in the analysis. Pooled analysis revealed that high IINS was significantly associated with poor OS (HR:2.54, 95% CI:1.84–3.50), PFS (HR:1.87,95% CI:1.06–3.31), DFS (HR:2.30,95% CI: 1.84–2.89) and RFS (HR:3.50,95% CI: 2.06–5.93). Subgroup analysis further demonstrated the strong prognostic value of high IINS for hepatocellular carcinoma and endometrial cancer.</p> Conclusions <p>The IINS could serve as an effective prognostic indicator for patients with cancers.</p>