I just testing my game on xcode (iPhone) to see how the ads works
But there has nothing ads to show at all.
or my game need to release on App Store first?
or I did something wrong?
Unity Ads can also be used on apps not released on the AppStore.
Please check if the test banner appears when playing in Unity Editor. There could be an integration issue.
If the banner is shown in the editor, there may not be any available banner ads in your region.
Also, the reason why the Game ID is not in the tutorial script is that the Game ID is only necessary when initializing the Unity Ads SDK.