theme preprocess view
I haven't found a way to do it in a THEME.theme file but I found a way to do it in a MODULE.MODULE file. The magic hook is MODULE_views_post_execute:

function feature_carrousel_views_post_execute(\Drupal\views\ViewExecutable $viewExecutable){
  /** @var \Drupal\views\Entity\View $view */
  $view = $viewExecutable-&gt;storage;
  if($view-&gt;id() == 'carrousel'){
    /** @var \Drupal\views\ResultRow $row */
    foreach($viewExecutable-&gt;result as $key =&gt; $row){
      $nid = $row-&gt;nid;
      /** @var \Drupal\node\NodeInterface $node */
      $node = \Drupal\node\Entity\Node::load($nid);
      if($node) {
        $country_filter = $node-&gt;get("field_country_filter")-&gt;getValue();
        $country_filter_tid = (reset($country_filter))['target_id'];
        /** @var \Drupal\taxonomy\Entity\Term $term */
        $term = \Drupal\taxonomy\Entity\Term::load($country_filter_tid);
        $name = $term-&gt;getName();
        $countryCode = getUserCountry();

        if(strtolower($name) != 'all' &amp;&amp; strtolower($name) != strtolower($countryCode)) {
          unset($viewExecutable-&gt;result[$key]);
          $viewExecutable-&gt;result = array_values($viewExecutable-&gt;result);
        }

      }
    }
  }
}


Cheers