If Al Nassr do not win the SPL or a famous competition Cristiano could leave. He signed for 2 years but Al Nassr are not allowed to force him to say. Cristiano must accept the second year deal otherwise he can leave as a free player. Al Nassr have Felix with Cristiano to score goals. They should win the SPL.
Cristiano Ronaldo will probably retire from football at the end of these two years anyway. That's why I don't think he'll leave the team. He could spend his final years here, earn a good living one last time, and then retire. Or, he could stay in Saudi Arabia and finish his career with Sporting Lisbon for one last year. Al-Nassr has a serious chance of winning the championship this year. The squad is well-built, and the team looks very good.