The Digital Twins (DTs) are introduced as part of the next level of process automation and control towards Construction 4.0 in the Architecture, Engineering, and Construction (AEC) industry to move the industry into the digital transformation era. DT is a vital enabling technology of construction 4.0 which has been widely applied in various industries to cover multiple lifecycle phases of systems, processes, and products. On the other hand, the Cognitive Digital Twin (CDT) concept, which is the next generation of DTs, has recently developed and reveals a prospective progression of the current DT concept toward a more intelligent, comprehensive, and full-lifecycle representation of complex systems. This chapter reviews previous studies pertinent to the CDT concept, its definitions, characteristics, and its required technologies.