Computational pathology (CP) is an interdiscipline formed by pathology and informatics techniques such as artificial intelligence and computer vision. The research field of CP has been rapidly broadened from lesion detection and immunohistochemistry quantification to predictions of molecular and prognostic properties. CP models, applied intensively in clinics and research, will become an essential assistant tool for diagnosis and disease management. In this paper, we aim to review recent developments in the field of CP, and discuss major challenges and potential solutions in practice and research.