As emerging networks put forward higher demands for end-to-end information processing capability in 6G communication, integrated sensing and communication technology has become a prevailing trend for the future development of 6G. By adopting the integrated sensing and communication technology, the integrated sensing system in 6G communication could implement various functions, such as spectrum sharing, hardware sharing, and signal sharing, so as to further enable real-time monitoring, tracking, identification, and imaging of targets or objects, and to meet the needs of users in a better way. By separating communication and sensing, the integrated system could enhance both the performance of integration and collaboration. In this paper, with the purpose of discussing the application scenarios and performance metrics for integrated sensing and communication in depth, we also highlight the analysis of key technologies such as system architecture, air interface integration, and network integration. Our aim is to achieve an effective operation of the integrated system.