In a sequel series to Blue Lock, the players could face challenges such as competing against stronger opponents, dealing with internal team conflicts, adapting to new playing styles or strategies, overcoming injuries or fatigue, facing unexpected setbacks or surprises during matches, and striving to maintain their individual skills while also working together as a team. Additionally, they may encounter new rivalries, experience pressure from fans and media, and have to navigate the complexities of fame and success in the world of professional soccer.