How to add custom taxonomy in custom post type permalink?

First, register your taxonomy and set the slug argument of rewrite to shows:

register_taxonomy(    'campaign',    'asset',    array(        'rewrite' => array( 'slug' => 'shows', 'with_front' => false ),        // your other args...    ));

Next, register your post type and set the slug to shows/%show_category%, and set has_archive argument to shows:

register_post_type(    'show',    array(        'rewrite' => array( 'slug' => 'campaign/%asset%', 'with_front' => false ),        'has_archive' => 'asset',        // your other args...    ));

Last, add a filter to post_type_link to substitute the show category in individual show permalinks:

function wpa_show_permalinks( $post_link, $post ){    if ( is_object( $post ) && $post->post_type == 'asset' ){        $terms = wp_get_object_terms( $post->ID, 'campaign' );        if( $terms ){            return str_replace( '%campaign%' , $terms[0]->slug , $post_link );        }    }    return $post_link;}add_filter( 'post_type_link', 'wpa_show_permalinks', 1, 2 );

First, register your taxonomy, then register your custom post type. You may also need to save your permalinks. I don't think you want 'with_front' set to true. The rest may be ok, but here's a working example.

/** * Register a 'campaign' taxonomy for post type 'asset'. * * @see register_post_type for registering post types. */function wpdocs_create_campaign_tax_rewrite() {    register_taxonomy( 'campaign', 'asset', array(        'rewrite' => array(            'slug' => '',            'with_front' => false,        ),    ) );}add_action( 'init', 'wpdocs_create_campaign_tax_rewrite', 0 );/** * Implements init_hook to register post type. * https://codex.wordpress.org/Function_Reference/register_post_type */function generic_create_posttype_asset() {    register_post_type(        'asset',        array(            'labels'       => array(                'name'          => __( 'Assets' ),                'singular_name' => __( 'Assets' ),                'add_new'       => __( 'New Asset' ),                'add_new_item'  => __( 'New Asset' ),                'edit_item'     => __( 'Edit Asset' ),            ),            'description'  => 'Campaign ...',            'public'       => true,            'hierarchical' => true,            'has_archive'  => true,            'rewrite' => array(                'slug' => '%campaign%',                'with_front' => false,            ),            'show_in_menu' => true,            'menu_icon'    => 'dashicons-category', // https://developer.wordpress.org/resource/dashicons/ .            'supports'     => array( 'title', 'editor', 'revisions', 'thumbnail' ),        )    );}add_action( 'init', 'generic_create_posttype_asset' );/** * Rewrite '%campaign%' with taxonomy assigned. */function asset_show_permalinks( $post_link, $post ){    if ( is_object( $post ) && $post->post_type == 'asset' ){        $terms = wp_get_object_terms( $post->ID, 'campaign' );        if( $terms ){            return str_replace( '%campaign%' , $terms[0]->slug , $post_link );        }    } else {            return $post_link;    }}add_filter( 'post_type_link', 'asset_show_permalinks', 1, 2 );function generic_cpt_rewrite_flush() {    generic_create_posttype_asset();    flush_rewrite_rules();}register_activation_hook( __FILE__, 'generic_cpt_rewrite_flush' );