Abstract: Objective: To evaluate the value of serological nutritional immunoinflammatory indicators for predicting the prognosis of patients with relapsed or metastatic esophageal squamous cell carcinoma (R/M ESCC) treated with camrelizumab combined with radio (chemo) therapy. Methods: From January 2018 to March 2021, 48 R/M ESCC patients who met the inclusion criteria were screened from The Forth Hospital of Hebei Medical University for retrospective analysis. According to the receiver operating characteristics (ROC) curve, the optimal threshold values of the prognostic nutritional index (PNI), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and systemic immune-inflammation index (SII) were determined. SPSS 25.0 software was used to perform univariate and multivariate statistical analyses. Results: The one- and two-year rates of overall survival (OS) and progression-free survival (PFS) after second-line immunotherapy were 42.9%, 22.5%, and 29.0%, 5.8%, respectively. The median OS and PFS were 9.0 months (95%CI: 6.4–11.7) and 8.5 months (95%CI:1.5–5.6), respectively. The multivariate analysis results showed that the combined methods of immunization, short-term efficacy, PNI, NLR, PLR, and SII were independent prognostic factors affecting patients’ OS (P=0.044, 0.030, 0.000, 0.040, 0.044, and 0.036, respectively). The independent prognostic factors for PFS were the combined methods of immunization, number of immunotherapy cycles, short-term efficacy, PNI, NLR, PLR, and SII (P=0.049, 0.024, 0.003, 0.017, 0.008, 0.000, and 0.009, respectively). Conclusions: Low PNL, high NLR, PLR, and SII values are independent predictors of poor prognosis for R/M ESCC after second-line therapy with a combination of camrelizumab and radiotherapy. alues are independent predictors of poor prognosis for R/M ESCC after second-line therapy with a combination of camrelizumab and radiotherapy.