The theoretical calculation of the anomalous magnetic moment of the muon (a_mu) encounters challenges in the low-energy region due to the strong interaction coupling constant alpha_s. Overcoming this limitation, a dispersion relation involving the cross section of e+e- annihilation to hadrons emerges as a promising method for a_mu measurement. Currently, the precision of the measurement is systematically challenged, necessitating a meticulous approach to obtain an accurate estimate of a_mu. With high luminosity and state-of-the-art detector, the Belle II experiment in Japan has the advantage to improve the systematics of the measurement. Using the unique capabilities of the Initial State Radiation (ISR) method we enhance the precision of this measurement. Addressing these challenges is imperative to improve our understanding of fundamental physics and reconcile theoretical predictions with experimental observations.