 Two-dimensional, 2D, materials have attracted significant interest due to their unique physical properties such as optical, electrical, mechanical, and magnetic. The combination of these materials into heterostructures has enabled the exploration of novel physics which cannot be accessed in single 2D materials or three-dimensional, 3D, heterostructures. Recent advances in the synthesis of high-quality 2D heterostructures have led to the design and fabrication of various heterostructure devices with remarkable performance. These include tunnelling transistors, photodetectors, and spintronics devices. This review summarizes recent developments in the fabrication, properties, and applications of 2D heterostructures, followed by discussion of current challenges and future prospects. This article was authored by Yen Pinglu, Su Xion, Juni, and others.