For many years, the prevailing idea was that heads of state were immune from trial and prosecution by the courts of heads of state. Therefore, heads of state were not prosecuted for crimes they committed, and there are many historical cases in this regard. However, this idea changed with the formation and development of international criminal law. One of these cases is the trial of Omar al-Bashir, which brought many challenges. The findings and conclusions of the article, which are written in a descriptive-analytical manner, indicate that today, gross violations of the Geneva Conventions have been criminalized, and with the establishment of the International Criminal Court, the concept of immunity for heads of state has changed, and if heads of state commit international crimes, they are tried and punished. However, the international custom governing states still poses difficulties in implementing it. The defiance of the South African government despite the order of the International Criminal Court to arrest Omar al-Bashir and the South African High Court indicates the resistance of states against the removal of state immunity. Because there is still support for heads of state beyond the rulers' ideology, and therefore cooperation with the International Criminal Court to prosecute heads of state requires time. One of these cases that was accompanied by great challenges was the trial of Omar al-Bashir, which showed that the sovereignty-oriented ideology still does not have the capacity for this transformation.