For UITableViewCells and UICollectionViewListCells, their contentView.layoutMarginsGuide respect the colletionView's layoutMarginsGuide automatically, which can be 16 or 20 points horizontally. This is the expected behavior. But for regular UICollectionViewCells with a regular compositional layout, their contentView.layoutMarginsGuide are defaulted to 8 points. I don't see where I can hook into and change the layout margins of the cells . I've looked into contentInset property and contentInsetReference property of section and item when constructing a compositional layout, but with no luck, their intentions are to change the width of the cells themselves.