The Cross Promotion Callout is used to display for desktop - a promo on the left and a carousel with scroll of up to 5 content cards on the right,  and for mobile - stacked with all cards displayed (no scroll). The Cards selection allows for selecting Content Lake content types as well as core site pages that inherit from the PromotableItem base template (L1-L4 content pages). 

Note: In Experience Editor, the scroll carousel is disabled and the cards stack on top of each other to allow ease of editing/updating.

Additional documentation.