[3] He was named the California Gatorade Player of the Year as a junior after averaging 16.9 points, 4.7 rebounds, and four assists per game.

[5] McCain averaged 17.7 points, 7.1 rebounds, four assists, and 1.5 steals per game for Centennial during the season and repeated as the California Gatorade Player of the Year.

[7][8] On March 18, 2022, he committed to playing college basketball for Duke over offers from Gonzaga, Kansas, and Houston.

[13] On January 29, 2024, McCain earned Atlantic Coast Conference (ACC) rookie of the week honors.

[14] On February 17, 2024, McCain scored a career-high 35 points, tying Zion Williamson for the Duke freshman record, in a 76–67 victory against Florida State.

[24] On December 14, it was announced that he had suffered a meniscus tear in his left knee and would not return to the court for an indefinite period of time.