5G technology has led a revolution in the communications industry and its performance enhancement in the FDD (Frequency Division Duplex) band is attracting a lot of attention. This paper aims to delve into the spectrum sharing revolution of 5G in the FDD band and how spectrum sharing is a key factor in achieving better performance and higher efficiency. With the advent of the digital age, communication networks have become an integral part of people's lives and work, and the introduction of 5G will support future communication needs like never before. 5G's performance varies across frequency bands, so it is critical to understand how to maximize the potential of the FDD band. The FDD band is in the spotlight because of its global deployment and wide range of applications, but its unique characteristic of having separate frequencies for uplink and downlink communications results in a waste of spectrum resources. This waste not only limits the band's capacity but also raises the cost of network operations, so innovative solutions are needed to address this challenge.