Deep integration of cyber physical systems enables integrated energy systems to develop rapidly for achieving low-carbon and efficient social goals. Considering deep coupling relationship between various energy systems, energy networks and cyber networks, and the impact of multiple uncertainties on integrated energy systems, necessity of reliability assessment of comprehensive energy systems under the background of integration of cyber physical systems was outlined. Moreover, the equivalent multi-state time-varying reliability models corresponding to energy physical components and demand-side energy consumption were discussed. The analysis models and methods for the energy physical system, cyber system and energy cyber physical system were extensively addressed. In addition, considering the correlation between cyber systems and energy physics systems, a comprehensive reliability assessment framework for integrated energy cyber physical systems was proposed. Finally, possible research directions for reliability assessment of comprehensive energy systems were pointed out under new situations.