No hierarchy in wp_list_categories with child of and depth
Add ‘style’ => ‘list’ to arguments: wp_list_categories(array( ‘child_of’ => 15, ‘title_li’ => ”, ‘hide_empty’ => 0, //just in case if no posts in category ‘style’ => ‘list’, )); Your output should be: Boxer ● Fawn ● Brindle Rotweiler