Immune checkpoint inhibitors (ICIs) have significantly reshaped cancer therapy by reactivating antitumor immune mechanisms, leading to sustained clinical responses in a proportion of patients across various malignancies. Nevertheless, their overall therapeutic efficacy is still constrained by several factors, including intrinsic and acquired resistance, relatively low response rates, and the occurrence of immune-related adverse events, all of which limit their broader clinical benefit.. Recent research has therefore focused on integrating ICIs with emerging therapeutic modalities designed to enhance antitumor immunity, overcome resistance mechanisms, and improve patient stratification. This review provides a comprehensive overview of the biological principles underlying immune checkpoint blockade and summarizes current clinical evidence supporting combination strategies involving personalized mRNA neoantigen vaccines, bispecific antibodies, adoptive cellular therapies, Strategies involving microbiome-based interventions, artificial intelligence-assisted biomarker identification, and integrated multi-omics approaches have emerged as promising tools for advancing precision medicine and improving therapeutic decision-making. Particular attention is given to the evolving role of precision oncology approaches in identifying predictive biomarkers, distinguishing immunologically “hot” and “cold” tumors, and optimizing patient selection. In addition, the review discusses the management of immune-related toxicities, current clinical guidelines, and the challenges associated with translating innovative immunotherapy combinations into routine clinical practice. Collectively, the evidence suggests that the future of cancer immunotherapy lies in rationally designed, biomarker-guided combination strategies that integrate advanced technologies with immune checkpoint blockade to achieve more durable, personalized, and globally accessible cancer treatments.