To complement the usefulness of the 'Review' custom post type, I created a review-specific sidebar widget to display and link our Hotel Reviews and Gear Reviews archive page on our travel blog.

public function widget( $args, $instance ) {
  $title = apply_filters( 'widget_title', $instance['title'] );
  // before and after widget arguments are defined by themes
  echo $args['before_widget'];

  if ( ! empty( $title ) )
    echo $args['before_title'] . $title . $args['after_title'];

  // This is where you run the code and display the output
  $args = [
    'orderby'            => 'name',
    'order'              => 'ASC',
    'style'              => 'list',
    'show_count'         => 0,
    'hide_empty'         => 1,
    'use_desc_for_title' => 0,
    'child_of'           => 0,
    'feed'               => '',
    'feed_type'          => '',
    'feed_image'         => '',
    'exclude'            => '',
    'exclude_tree'       => '',
    'include'            => '',
    'hierarchical'       => 0,
    'title_li'           => __( '' ),
    'show_option_none'   => __( 'No reviews' ),
    'number'             => null,
    'echo'               => 1,
    'depth'              => 0,
    'current_category'   => 0,
    'pad_counts'         => 0,
    'taxonomy'           => 'review-type',
    'walker'             => null ];
  echo '<ul>';
  wp_list_categories( $args );
  echo '</ul>';

  echo '</aside>';
}
public function form( $instance ) {
    if ( isset( $instance[ 'title' ] ) ) {
      $title = $instance[ 'title'];
    }
    else {
      $title = __( 'New title', 'wpme-lifeph' );
    }
  // Widget admin form
  ?>
  <p>
  <label for="<?php echo $this->get_field_id( 'title' ); ?>"><?php _e( 'Title:' ); ?></label>
  <input class="widefat" id="<?php echo $this->get_field_id( 'title' ); ?>" name="<?php echo $this->get_field_name( 'title' ); ?>" type="text" value="<?php echo esc_attr( $title ); ?>" />
  </p>
  <?php 
  }
  	
  // Updating widget replacing old instances with new
  public function update( $new_instance, $old_instance ) {
  $instance = array();
  $instance['title'] = ( ! empty( $new_instance['title'] ) ) ? strip_tags( $new_instance['title'] ) : '';
  return $instance;
  }

The whole code