The High-Luminosity Large Hadron Collider (HL-LHC) upgrade will substantially increase the instantaneous luminosity, achieving values between \(5 \times 10^{34}~\text {cm}^{-2}~\text {s}^{-1}\) and \(7 \times 10^{34}~\text {cm}^{-2}~\text {s}^{-1}\) , approximately seven times the nominal level. This upgrade intensifies the particle flux, creating significant challenges for the forward sections of the Compact Muon Solenoid (CMS) detector. In response, new Gas Electron Multiplier (GEM) stations, GE2/1 and ME0, will be installed within the CMS muon system to strengthen its forward capabilities. The ME0 station is a pivotal addition to CMS, extending the detectors pseudorapidity coverage to the range \(2.03 < \eta < 2.80\) . This expansion takes advantage of CMS improved inner tracking capabilities and the optimized muon identification efficiency within the extended forward range, where particle flux is highest. Built on the successful performance of GEM technology in GE1/1, ME0 is designed to meet the demands of the HL-LHC environment with high spatial resolution and high rate capability. This note reports an overview of the CMS muon system upgrade with GEM technology, focusing on the ME0 upgrade. It covers the design and validation processes of an ME0 chamber, which is essential to this enhancement.