这应该会为你找到一位直系父母。

// get the current category ID
$category_id = get_the_category(get_the_ID());

// get the current category object
$child = get_category($category_id[0]->term_id);

// get it\'s parent object
$parent = get_category($child->parent);

var_dump($parent->name . \' - \' . $child->name);

$args = [
    \'post_type\' => \'post\'
];
$query = new WP_Query($args);

if ($query->have_posts()) {
    while ($query->have_posts()) {
        $query->the_post();
        // get the current category ID
        $category_id = get_the_category(get_the_ID());

        // get the current category object
        $child = get_category($category_id[0]->term_id);

        // get it\'s parent object
        $parent = get_category($child->parent);

        dump(get_the_title() . \': \' . $parent->name . \' - \' . $child->name);
    }
}