Liquid biopsy (LB) involves the molecular profiling of primarily peripheral blood for detecting genomic mutations and consists of a repeatable, noninvasive method to monitor for tumor recurrence. In the form of cell-free DNA (cfDNA), circulating tumor cells (CTCs), and exosomes, liquid biopsy forms a crucial part of precision oncology and detects alterations that form the prognostic and predictive biomarkers of tumors. Liquid biopsy samples can be quantitatively measured for determining the outcomes of personalized cancer medicines. LB forms an alternative to the diagnostic gold standard, which is considered tissue biopsy for prognosis, and treatment, but tissue biopsy remains challenging due to its invasive nature and lack of ability to detect tumor heterogeneity. Liquid biopsy is able to dynamically monitor tumors both spatially and temporally and can measure minimal residual disease to determine the risk of recurrence. However, due to its limitations, having less sensitivity and specificity than tumor biopsy, it has not been fully implemented in the clinic and remains a complementary tool to tissue biopsy.