Don't highlight a card with a colored side border; use a Badge in the header.
Accessibility
A card is a visual grouping, not an ARIA role. A static card takes no focus just because it has a border.
Use headings that fit the page outline for card titles, and a list when cards form a collection.
Links navigate and buttons run actions. Don't nest a button or link inside another link; a secondary action (Favorite) never also opens the card's main destination.
Name links so they identify the card ("View Pro plan", not a row of "Learn more"). If the whole card area extends a link, the focus ring must show that area.
Informative images need useful alt text; decorative ones don't repeat the title.
Adapted from Magoo 1.6.0 by Marcelo Sales: Cards (cards). Magoo is educational guidance; test the behavior in your implementation.