function get_product_subcategories_list( $category_slug ){
$terms_html = array();
$taxonomy = 'product_cat';
// Get the product category (parent) WP_Term object
$parent = get_term_by( 'slug', $category_slug, $taxonomy );
// Get an array of the subcategories IDs (children IDs)
$children_ids = get_term_children( $parent->term_id, $taxonomy );
// Loop through each children IDs
foreach($children_ids as $children_id){
$term = get_term( $children_id, $taxonomy ); // WP_Term object
$term_link = get_term_link( $term, $taxonomy ); // The term link
if ( is_wp_error( $term_link ) ) $term_link = '';
// Set in an array the html formated subcategory name/link
$terms_html[] = '<div><a href="' . esc_url( $term_link ) . '" rel="tag" class="' . $term->slug . '">' . $term->name . '</a></div>';
}
return '<span class="subcategories-' . $category_slug . '">' . implode( '', $terms_html ) . '</span>';
}