wp-metabox-with-custom-page-template

    $cmb = new_cmb2_box( array(
        'id'           => 'feature_food_carousel',
        'title'        => 'Feature food carousel product price',
        'object_types' => array( 'page' ),
        'show_on' => array( 'key' => 'page-template', 'value' => 'front-page.php'),
        'context'      => 'normal',
        'priority'     => 'high',
        'show_names'   => true,
    ));