Professional baseball leagues are organized competitions where teams of players compete at a high level. The most prominent league in the United States is Major League Baseball (MLB), which features teams from both the American League and the National League. These leagues are known for their rich history, fan engagement, and the development of talented players. In addition to MLB, there are various minor leagues that serve as a developmental system for aspiring players. These leagues, such as the Triple-A and Double-A leagues, provide opportunities for players to showcase their skills and potentially advance to the major leagues. International leagues, like the Korean Baseball Organization (KBO) and Japanese Nippon Professional Baseball (NPB), also contribute to the global popularity of the sport.