You can remove products from campaigns at three different locations: in the campaign view, in the product card, and in the product form.
1) Campaign view
2) In the product card
In the product card's Pricing tab, you can see all the campaigns that the product belongs to. In this view, you can also remove the product from the campaign by clicking the Delete link on the left side of the selected campaign's row.
3) On the product form
You can also remove a product from a campaign in the product form, for example, when editing product details.
In the product form's Pricing section, you can see all the campaigns that the product belongs to. This is where you can remove the product from the desired campaign by clicking the Delete link in the campaign's row.