Immunotherapeutics in metastatic cancer management

Metastatic cancer remains the leading cause of cancer-related mortality, largely owing to the limitations of conventional treatments such as chemotherapy, radiotherapy, and targeted agents that are challenged by tumor heterogeneity, acquired resistance, and systemic toxicity. In contrast, immunotherapy has emerged as a transformative modality, harnessing the power of the immune system to selectively target and eradicate tumor cells. This review systematically examines key immunotherapeutic strategies ranging from immune checkpoint inhibitors (ICIs) and monoclonal antibodies to cancer vaccines, oncolytic viruses, and adoptive cell therapies (such as CAR-T and TCR-engineered T cells). Of particular interest are personalized approaches, including neoantigen-based vaccines and tumor-infiltrating lymphocyte (TIL) therapies, which hold promise for tailored treatment but also present significant logistical and translational challenges. Central to therapeutic outcomes are factors like immune resistance, the suppressive tumor microenvironment, and the identification of predictive biomarkers including PD-L1 expression and tumor mutational burden (TMB) that can guide patient selection and efficacy. As the field progresses, future breakthroughs will hinge on deepening our understanding of metastasis immunobiology, refining biomarker-driven precision approaches, and developing novel immunological targets and delivery platforms to improve outcomes and accessibility.