This article provides a comprehensive overview of the roles and definitions of biomarkers in clinical research. Biomarkers are objective, measurable characteristics of biological processes that can be used to predict or indicate clinical outcomes. The authors distinguish between biomarkers, clinical endpoints, and surrogate endpoints. Biomarkers are broad medical signs that can be quantified, while clinical endpoints reflect a patient's health and well-being. Surrogate endpoints are specific, well-characterized biomarkers that can predict clinically meaningful outcomes but are not direct replacements for clinical endpoints. The article emphasizes the importance of evaluating the relevance and validity of biomarkers as surrogates, noting that their use should be provisional and continuously reevaluated. Misuse of biomarkers can lead to flawed research conclusions and inappropriate treatment approvals. The FDA allows the use of biomarkers as surrogate endpoints in drug development, but requires follow-up studies to confirm their effectiveness. The article concludes that while biomarkers are crucial for advancing drug development and biomedical research, their use must be carefully managed to avoid misleading or harmful outcomes.This article provides a comprehensive overview of the roles and definitions of biomarkers in clinical research. Biomarkers are objective, measurable characteristics of biological processes that can be used to predict or indicate clinical outcomes. The authors distinguish between biomarkers, clinical endpoints, and surrogate endpoints. Biomarkers are broad medical signs that can be quantified, while clinical endpoints reflect a patient's health and well-being. Surrogate endpoints are specific, well-characterized biomarkers that can predict clinically meaningful outcomes but are not direct replacements for clinical endpoints. The article emphasizes the importance of evaluating the relevance and validity of biomarkers as surrogates, noting that their use should be provisional and continuously reevaluated. Misuse of biomarkers can lead to flawed research conclusions and inappropriate treatment approvals. The FDA allows the use of biomarkers as surrogate endpoints in drug development, but requires follow-up studies to confirm their effectiveness. The article concludes that while biomarkers are crucial for advancing drug development and biomedical research, their use must be carefully managed to avoid misleading or harmful outcomes.