This comprehensive article details a high-precision measurement of the W boson mass (mW), a fundamental parameter in particle physics, conducted by the CMS Collaboration. The study emphasizes the meticulous calibration of muon momentum using dimuon decays, crucial for minimizing systematic uncertainties. It also addresses the theoretical modeling of W boson production, employing sophisticated techniques like the "helicity fit" to reduce reliance on theoretical predictions and validate results against Z boson measurements. The paper outlines background estimation, various uncertainty sources, and comparisons with other experimental results, notably highlighting a discrepancy with the CDF Collaboration's measurement.