@iccohen that’s an ad notification, which is part of Brave Rewards. They show because you enabled it.
https://brave.com/brave-rewards/
https://support.brave.com/hc/en-us/categories/360001053052-Rewards
To turn them off, go to Brave Rewards and disable it.
You’ll see in the screenshot above there’s a toggle for Notification Ads and New tab page ads.
And more on types of ads you can see as part of Brave Rewards can be seen at part of my FAQ: What types of ads are there?