When Leona, Determined attacks and stuns a defender, what happens if the defender doesn't die?

The stunned defender remains on the battlefield and doesn't deal combat damage that turn, while Leona (the attacker) is automatically recalled back to your base. Here's the sequence: (1) Leona attacks and her ability stuns an enemy unit at the battlefield, (2) Combat occurs where the stunned unit deals 0 damage to Leona while Leona deals her damage normally, (3) If the defender survives, Leona is automatically recalled to your base during Combat Cleanup (attackers are recalled if defenders are still present), and the stunned defender stays at the battlefield. The stun effect only prevents the unit from dealing combat damage that turn - it doesn't kill the unit. Any damage marked on the defender heals during Combat Cleanup. If Leona had killed all defenders, she would stay and conquer the battlefield instead of being recalled.