How to create sub menu in Drupal 8 using views result for specific item of the menu?
We have implemented using the 

MODULE_NAME_menu_links_discovered_alter(&amp;$links).


In which, We have accessed the result of the block by using the following code.

 $result = views_get_view_result("view_name", "display_id");
    foreach($result as $result) {
      $title = "Entertainment"; // we have took as static
      $tid = 10;
      $slug = str_replace(' ', '_', strtolower($title));
      $links[$slug] = array(
        'title' =&gt; $title,
        'route_name' =&gt; 'view.VIEW_NAME.DISPLAY_ID'
        'route_parameters' =&gt; array('arg_0' =&gt; $tid),
        'description' =&gt; 'Dynamic',
        'provider' =&gt; 'MODULE_NAME',
        'parent' =&gt; 'menu_link_content:DATABASE_UUID_OF_SELECTED_CATEGORY',
        'id' =&gt; $slug
      );
    }


We have used route_name for assigning the url, this url should be the existing url of the drupal site.

We need route_parameters for passing the arguments.

For accessing the Video Link : reference in parent of $links. I have got it from the 

SELECT uuid as DATABASE_UUID_OF_SELECTED_CATEGORY FROM `menu_link_content` where id = "TID_Video_Link_of_Main_menu"


After that, We have used that id in parent as 'menu_link_content:04c479c9-7234-4de2-a4f0-e03b0a3003b6' so all links will be added below the Video Link of the main menu.

After doing all the code and we need to clear the cache. And we are able to see the sub menu from the views of texonomy to Video Link of the main menu.

Please suggest me if there is any better way than this.

For Reference: https://api.drupal.org/api/drupal/core!lib!Drupal!Core!Menu!menu.api.php/function/hook_menu_links_discovered_alter/8.2.x