$sku = $product->get_sku();
        if(!empty($sku)){
        printf( '<h1 class="header-section__title">%s</h1>', esc_html( $title ) );
        
        if ( $banner_subtitle ) {
            printf( '<p class="header-section__description">%s</p>', esc_html( $banner_subtitle ) );
        }
        }elseif {
            global $product;
        if ( $product->get_sku() ) {
            echo 'SKU: ', $product->get_sku();
        }
        }