Is there any difference between 学園 and 学校?

学園 is commonly translated as "Academy". Basically it is nothing more than a naming convention which is arbitrarily adopted for the names of some schools (including 中学校, 高校, 大学, 予備校 and 塾). So all schools called 学園 are technically also 学校, but the opposite is not true. As a minor exception, 学園 is found in some place names of science parks and university towns (e.g., 筑波研究学園都市). 学院 is almost the same but it's not used as a place name.

Most real 学園/学院 in Japan are private schools, but there are a few exceptions. In addition, I feel that schools that are considered "unique", "classy" or "special" in some way or another tend to be called 学園/学院. For example, Christian schools in Japan are commonly called ～学園 or ～学院. In fiction, students in Kaguya-sama and the Toaru franchise go to schools called ～学園. 魔法学園 are very common in fantasy works.