run loop with cmb2 metaboxes,

index.php

<!--front end html loop-->
<ul class="social">
        <?php
          $entries = get_post_meta( get_the_ID(), '_yourprefix_main_boxes', true );

          foreach ( (array) $entries as $key => $entry ) {

             $icon_name = $link_irr = '';

            if ( isset( $entry['_yourprefix_font_icon'] ) ) {
              $icon_name = esc_html( $entry['_yourprefix_font_icon'] );
            }

            if ( isset( $entry['_yourprefix_pro_link'] ) ) {
              $link_irr = esc_html( $entry['_yourprefix_pro_link'] );
            }

            ?>


            <li><a href="<?php echo esc_html( $link_irr ); ?>"><i class="fab fa-<?php echo esc_html( $icon_name ); ?>"></i></a></li>

          <?php
          }
         ?>
      </ul>
<!--end frontent-->


<!--backend cmb2 function.php code-->
<?php
function awc_register_repeatable_group_field_metabox() {

    // Start with an underscore to hide fields from custom fields list
    $prefix = '_yourprefix_';

/**
 * Repeatable Field Groups
 */
$cmb_group = new_cmb2_box( array(
    'id'           => $prefix . 'about_boxes',
    'title'        => __( 'Social link', 'cmb2' ),
    'object_types' => array( 'about_us', ),
) );

// $group_field_id is the field id string, so in this case: $prefix . 'demo'
    $group_field_id = $cmb_group->add_field( array(
    'id'          => $prefix . 'main_boxes',
    'type'        => 'group',
    //'description' => __( 'Generates reusable form entries', 'cmb2' ),
    'options'     => array(
        'group_title'   => __( 'Social {#}', 'cmb2' ), // {#} gets replaced by row number
        'add_button'    => __( 'Add Another Link', 'cmb2' ),
        'remove_button' => __( 'Remove Link', 'cmb2' ),
        'sortable'      => true, // beta
    ),
) );

/**
 * Group fields works the same, except ids only need
 * to be unique to the group. Prefix is not needed.
 *
 * The parent field's id needs to be passed as the first argument.
 */
$cmb_group->add_group_field( $group_field_id, array(
    'name'       => __( 'Icon', 'cmb2' ),
    'id'         => $prefix .'font_icon',
    'type'       => 'text',
    'desc'		=>'Add font awesome5 icon, example=> fa-facebook-f'
) );

$cmb_group->add_group_field( $group_field_id, array(
    'name'       => __( 'Link', 'cmb2' ),
    'id'         => $prefix . 'pro_link',
    'type'       => 'text_url',
    'desc'		=>'Add Your social link URL'
) );

}


?>