Get posts in custom post type categories

You can use any of Category Parameters for your WP_Query

• cat (int) – use category id.
• category_name (string) – use category slug.
• category__and (array) – use category id.
• category__in (array) – use category id.

• category__not_in (array) – use category id.

  //list all posts by category
  $args = array(
      'post_type' => 'works', // NOT 'Works'
      // Add category id like this.
     'cat' => $cat_id
      );