Set taxonomy term filter labels to the taxonomy name

web/themes/asc_bootstrap/asc_bootstrap.theme

 <?php
+use \Drupal\taxonomy\Entity\Term;
+use \Drupal\taxonomy\Entity\Vocabulary;
+
 /**
  * @file
  * Bootstrap sub-theme.
@@ -126,9 +129,34 @@ function asc_bootstrap_form_alter(&$form, \Drupal\Core\Form\FormStateInterface $
     if(count($form['field_appointment_target_id']['#options']) == 0) {
       $form['field_appointment_target_id']['#access'] = FALSE;
     }
+    else {
+      $tid = array_shift(array_keys($form['field_appointment_target_id']['#options']));
+      $term = Term::load($tid);
+      if (!empty($term)) {
+        $vid = array_shift($term->vid->getValue())['target_id'];
+        if(!empty($vid)) {
+          $vocab = Vocabulary::load($vid);
+          $vocab_label = $vocab->get('name');
+          $form['#info']['filter-field_appointment_target_id']['label'] = $vocab_label;
+        }
+      }
+    }
+
     if(count($form['field_research_interests_target_id']['#options']) == 0) {
       $form['field_research_interests_target_id']['#access'] = FALSE;
     }
+    else {
+      $tid = array_shift(array_keys($form['field_research_interests_target_id']['#options']));
+      $term = Term::load($tid);
+      if (!empty($term)) {
+        $vid = array_shift($term->vid->getValue())['target_id'];
+        if(!empty($vid)) {
+          $vocab = Vocabulary::load($vid);
+          $vocab_label = $vocab->get('name');
+          $form['#info']['filter-field_research_interests_target_id']['label'] = $vocab_label;
+        }
+      }
+    }
   }
 
   /*
@@ -154,4 +182,4 @@ function asc_bootstrap_form_alter(&$form, \Drupal\Core\Form\FormStateInterface $
     $form['field_appointment_target_id']['#weight'] = 3;
     $form['field_research_interests_target_id']['#weight'] = 4;
   }
-}
+}
\ No newline at end of file