taxonomy-{taxonomy}-{term}.php

taxonomy-maintenance-professional.php

$args = array(
    'orderby'    => 'name',
    'order'      => 'ASC',
    'hide_empty' => TRUE,
    'fields'     => 'all',
);
$terms = get_terms( 'project_type', $args);

if (
    ! is_wp_error( $terms )
    && ! empty( $terms )
) {
    echo '<ul>';

    foreach ( $terms as $term ) {
        $url = get_term_link( $term );
        if ( is_wp_error( $url ) ) {
            continue;
        }

        $url = add_query_arg( 'post_type', 'projects', $url );
        printf(
            '<li><a href="%s">%s</a></li>',
            $url,
            $term->name
        );
    }

    echo '</ul>';
}

$post_type = get_post_type();

  if ( is_post_type_archive() ) {
    $taxonomies = get_object_taxonomies($post_type);
    $related_terms = get_terms(array(
      'taxonomy' => $taxonomies
    ));
  }

if ( !empty($related_terms) && !is_wp_error($related_terms) ) {
    foreach ( $related_terms as $related_term ) {
      $term_url = get_term_link($related_term);

      if ( is_post_type_archive() ) {
        $term_url = add_query_arg( 'post_type', $post_type, $term_url );
      }
?>
  <a href="<?php echo esc_url($term_url); ?>"><?php echo $related_term->name; ?></a>
<?php    }
  }