Among heterocyclic compounds, quinoline stands out as a highly advantageous scaffold and serves as a significant foundation for developing new drug entities. Quinoline and its derivatives, tested for various biological activities, represent an essential class of compounds in drug development. Consequently, numerous scientific communities have focused on creating these compounds as key structures and assessing their biological activities. This review offers an overview of the natural sources of quinoline, highlights marketed drugs based on quinoline, and examines the biological activities of quinoline derivatives. Quinoline compounds hold considerable medicinal value, particularly in cancer treatment. However, challenges such as drug resistance and potential toxicity can limit their effectiveness. There is a need for new derivatives that minimize harm to normal cells and reduce side effects, aiming for better treatment outcomes.