Invalidate a specific cache tag on any saved taxonomy term I would like to clear cache tag of a particular bundle when any taxonomy terms are update/ saved. 

I know the default node tag is saved like node:1, node:2, but I'm confused on how to invalidate a particular bundle.
You don't invalidate entity tags, Drupal does this automatically on CRUD operations.

Instead add a cache tag to all nodes of the specific content type:

/**
 * Implements hook_preprocess_node()
 *
 */
function mymodule_preprocess_node(&amp;$variables) {
  if ($variables['node']-&gt;getType() === 'my_content_type') {
    $variables['#cache']['tags'][] = 'taxonomy_term_list';
  }
}


The tag taxonomy_term_list gets invalidated on any taxonomy term saved/updated/deleted.