COVICI-SURV is a nationwide, retrospective observational cohort study using the French national health data system (SNDS) to evaluate whether COVID-19 vaccination, particularly mRNA vaccination, received within 100 days before or after immune checkpoint inhibitor (ICI) initiation is associated with survival among adults with cancer. The cohort includes 95,015 adults initiating anti-PD-1, anti-PD-L1 or anti-CTLA-4 therapy between 28 December 2020 and 22 March 2023. Pre-ICI vaccination is analysed using inverse probability of treatment weighting, and post-ICI vaccination among patients without COVID-19 vaccination in the preceding 100 days is analysed using a cloning-censoring-weighting target-trial emulation. The primary outcome is all-cause mortality; secondary outcomes include cancer-specific mortality, non-COVID-19 mortality and real-world progression-free survival. Follow-up extends to 31 December 2024 for all-cause mortality and to 31 December 2023 for cause-specific mortality.