Newly uploaded creatives are added to a moderation queue and need to be reviewed before they can be set to live. Our moderation team reviews every creative submission to ensure they follow our content policy, and this process typically takes less than 48 hours.
https://docs.unity.com/acquire/en/manual/creative-moderation
Our Advertising Content Policy can be found here:
https://unity3d.com/legal/advertising-content-policy