Objective. To evaluate the prognostic value of the immune checkpoint inhibitor prognostic index (ICPI), based on the albumin (ALB) and derived neutrophil-to-lymphocyte ratio (dNLR), for nonsmall cell lung cancer (NSCLC) patients receiving immune checkpoint inhibitors (ICIs). Methods. We conducted a multicentre retrospective study with an ICIs cohort (n = 143) and a chemotherapy control cohort (n = 84). A Cox proportional hazards regression and logistic regression model were used to find the independent risk factor for progression-free survival (PFS) and overall survival (OS) and disease control rate (DCR) in NSCLC patients. The Kaplan–Meier was used to evaluating the PFS and OS. Results. The ALB <35 g/L and dNLR >3 were correlated with worse PFS and OS for NSCLC patients receiving ICIs, respectively. The moderately high-risk ICPI had a significantly increased risk of progression (hazard ratio (HR) 1.83, 95% confidence interval (CI) 1.14–2.91; P = 0.012 ) and of death (HR 2.33, 95% CI 1.12–4.87; P = 0.024 ) and of nondisease control (odds ratio (OR) 3.05, 95% CI 1.19–7.83; P = 0.021 ) and was correlated with worse PFS and 1-year survival rates (4.0 months vs. 7.2 months; P = 0.001 ; 44.3% vs. 76.1%; P = 0.001 ) compared with low-risk ICPI when it was characterized two groups. When ICPI was further divided into three groups, the results showed that the high-risk ICPI was correlated with worse PFS and 1-year survival rates. However, there was no difference in the chemotherapy cohort. Conclusion. The ICPI was correlated with worse outcomes for NSCLC patients receiving ICIs but not for patients with chemotherapy.