Cléon, champion joyeux

You pay all costs and follow all timing rules for cards played with the permission granted by Cleon's last ability. For example, if the exiled card is a land card, you may play it only during your main phase while the stack is empty.

Cleon's second ability resolves before the spell that caused it to trigger. It resolves even if that spell is countered or otherwise leaves the stack without resolving.