Popups display on top of your site and show information that the visitor must react to. Focus is moved inside the popup modal and the visitor must close out the popup to continue engaging with other content on your site. Popups are obtrusive and should be used with caution and consideration.
Different then popups slide-ins do not require action from the visitor. While they can still be obtrusive and prevent the user from seeing the parts of your page they cover up, they do not hide all your content or prevent the user from clicking on other items on your page.
Banners are similar to slide-ins in that they are less obtrusive than popups (the user is not required to react to them to engage with the rest of your site). They cover the full-screen width and when the visitor is scrolled to the top or bottom of a page the banner will be offset so the entire page content can be accessed and seen while a banner is active.