<?php $current_term = get_term_by( 'slug', get_query_var( 'term' ), get_query_var( 'taxonomy' ) ); //this is alraedy called on top of taxonomy-term.php file ?>

<ul class="list-child-pages">
  <?php
    $args = array(
      'taxonomy' => 'benefit-category',
      'orderby' => 'menu_order',
      'hide_empty' => true,
    );
  ?>
  <?php $benefit_categories = get_terms($args); ?>
  <?php foreach ( $benefit_categories as $benefit_category ) { ?>
    <li <?php if ( $current_term->slug == $benefit_category->slug ) { ?> class="current-term" <?php } ?>>
      <a href="<?php echo home_url(); ?>/benefit-category/<?php echo $benefit_category->slug; ?>"><?php echo $benefit_category->name; ?></a>
    </li>
  <?php } ?>
</ul>