Compared with traditional satellite communication systems, the recent advancement by 5G non-terrestrial network (NTN) technology offers a disruptive solution by enhancing mobile cellular technology to support satellite communications. It allows satellite operators to leverage the mobile cellular ecosystem and its economies of scale to penetrate satellite communications from a niche market to mainstream consumer market. On the other hand, it also facilitates the integration between the networks operated by terrestrial and satellite operators via the common radio/core network technology and architecture. With the key enabler by multi-mode devices, which could flexibly switch between terrestrial and satellite networks, NTN technology can turn terrestrial and satellite operators from competitors toward partners (e.g., complement service coverage, traffic roaming, and service platform). It is generally believed that satellite and terrestrial network convergence will be a mega trend from 5G toward 6G. The following sections will further investigate the potential use cases and advantages.