The treatment of cancer has remarkably improved because of increased knowledge of the abnormalities at the molecular level, which results in human cancer growth. This has initiated the development of ever more successful as well as effective targeted cancer therapies. Detection of cancer is diagnosed basically by performing routine biopsy/cytology, which has many drawbacks. Therefore, the concept of liquid biopsy has been introduced to oncology, which has the potential to revolutionise the management of cancer patients, eliminating the invasive procedures needed to obtain tissue samples and provide information. Liquid biopsy is the analysis of tumour cells or tumour cell products obtained from blood or other body fluids, providing a broad range of opportunities in the field of pathology. Here, we focus on the most prominent liquid biopsy markers, circulating tumour cells and circulating tumour-derived deoxyribonucleic acid (DNA), in the blood of patients. In this review, we discuss recent clinical studies on these biomarkers for early detection and prognostication of cancer, which helps in successful management. Hence, liquid biopsy is introduced with great promise for personalised medicine because of its ability to provide multiple non-invasive snapshots of the primary and metastatic tumours.