For decades, biomarkers have been employed in clinical practise. Biomarker studies have entered a new age with the rise of genomics and other advancements in molecular biology, and they hold promise for early diagnosis and successful treatment of many diseases. A biomarker is a measurable trait that can be used to assess normal biological processes, pathogenic processes, or pharmacologic reactions to a treatment intervention. They are divided into five categories based on their use in different stages of disease: antecedent biomarkers, which identify the risk of developing an illness, screening biomarkers, which screen for subclinical disease, diagnostic biomarkers, which recognise overt disease, staging biomarkers, which categorise disease severity, and prognostic biomarkers, which predict future disease course, including recurrence, response to therapy, and therapy monitoring efficacy. Biomarkers can reflect a number of health or disease features, such as the amount or kind of environmental exposure, genetic vulnerability, genetic responses to environmental exposures, markers of subclinical or clinical disease, or indicators of therapy response. Biomarkers have been employed in public health and clinical practise, as well as preventive medicine, diagnostics, treatments, and prognostics.