diff --git a/src/Domain/CampoKeys.php b/src/Domain/CampoKeys.php
index 7788684..48128bd 100644
--- a/src/Domain/CampoKeys.php
+++ b/src/Domain/CampoKeys.php
@@ -5,7 +5,7 @@
 namespace Fau\DegreeProgram\Common\Domain;
 
 /**
- * @psalm-type CampoKeysMap = array<value-of<self::SUPPORTED_CAMPO_KEYS>, string>
+ * @psalm-type CampoKeysMap = array<value-of<self::SUPPORTED_CAMPO_KEYS>, array<int, string>>
  */
 final class CampoKeys
 {
@@ -13,13 +13,13 @@ final class CampoKeys
         'type' => 'object',
         'properties' => [
             DegreeProgram::DEGREE => [
-                'type' => 'string',
+                'type' => 'array',
             ],
             DegreeProgram::AREA_OF_STUDY => [
-                'type' => 'string',
+                'type' => 'array',
             ],
             DegreeProgram::LOCATION => [
-                'type' => 'string',
+                'type' => 'array',
             ],
         ],
     ];
@@ -28,13 +28,13 @@ final class CampoKeys
         'type' => 'object',
         'properties' => [
             DegreeProgram::DEGREE => [
-                'type' => 'string',
+                'type' => 'array',
             ],
             DegreeProgram::AREA_OF_STUDY => [
-                'type' => 'string',
+                'type' => 'array',
             ],
             DegreeProgram::LOCATION => [
-                'type' => 'string',
+                'type' => 'array',
             ],
         ],
     ];
@@ -45,8 +45,6 @@ final class CampoKeys
         DegreeProgram::LOCATION,
     ];
 
-    private const HIS_CODE_DELIMITER = '|';
-
     private function __construct(
         /**
          * @var CampoKeysMap $map
@@ -68,18 +66,6 @@ public static function fromArray(array $map): self
         return new self($map);
     }
 
-    public static function fromHisCode(string $hisCode): self
-    {
-        $parts = explode(self::HIS_CODE_DELIMITER, $hisCode);
-        $map = [
-            DegreeProgram::DEGREE => $parts[0] ?? null,
-            DegreeProgram::AREA_OF_STUDY => $parts[1] ?? null,
-            DegreeProgram::LOCATION => $parts[6] ?? null,
-        ];
-
-        return new self(array_filter($map, fn($value) => !is_null($value)));
-    }
-
     /**
      * @return CampoKeysMap
      */
diff --git a/src/Infrastructure/Repository/CampoKeysRepository.php b/src/Infrastructure/Repository/CampoKeysRepository.php
index 3031a45..3cd6f3e 100644
--- a/src/Infrastructure/Repository/CampoKeysRepository.php
+++ b/src/Infrastructure/Repository/CampoKeysRepository.php
@@ -24,6 +24,8 @@ final class CampoKeysRepository
 
     public const CAMPO_KEY_TERM_META_KEY = 'uniquename';
 
+    private const HIS_CODE_DELIMITER = '|';
+
     public function degreeProgramCampoKeys(DegreeProgramId $degreeProgramId): CampoKeys
     {
         /** @var WP_Error|array<WP_Term> $terms */
@@ -51,7 +53,7 @@ public function degreeProgramCampoKeys(DegreeProgramId $degreeProgramId): CampoK
                 continue;
             }
 
-            $map[$campoKeyType] = $campoKey;
+            $map[$campoKeyType][$term->term_id] = $campoKey;
         }
 
         return CampoKeys::fromArray($map);
@@ -60,29 +62,23 @@ public function degreeProgramCampoKeys(DegreeProgramId $degreeProgramId): CampoK
     /**
      * Return a map of taxonomy keys to terms based on a given HIS code.
      *
-     * @throws RuntimeException
      * @return array<string, int>
      */
-    public function taxonomyToTermsMapFromCampoKeys(CampoKeys $campoKeys): array
+    public function taxonomyToTermsMapFromHisCode(string $hisCode): array
     {
         $result = [];
 
-        $campoKeys = $campoKeys->asArray();
+        $campoKeys = $this->campoKeysFromHisCode($hisCode);
 
         foreach (self::TAXONOMY_TO_CAMPO_KEY_MAP as $taxonomy => $campoKeyType) {
-            $campoKey = $campoKeys[$campoKeyType] ?? '';
+            $campoKey = $campoKeys[$campoKeyType] ?? null;
 
-            if ($campoKey === '') {
+            if (!is_string($campoKey) || $campoKey === '') {
                 continue;
             }
 
             $term = $this->findTermByCampoKey($taxonomy, $campoKey);
-
-            if (! $term instanceof WP_Term) {
-                throw new RuntimeException('Could not find term for Campo key: ' . $campoKey);
-            }
-
-            $result[$taxonomy] = $term->term_id;
+            $result[$taxonomy] = $term instanceof WP_Term ? $term->term_id : 0;
         }
 
         return $result;
@@ -107,4 +103,16 @@ private function findTermByCampoKey(string $taxonomy, string $campoKey): ?WP_Ter
 
         return $terms[0] ?? null;
     }
+
+    public function campoKeysFromHisCode(string $hisCode): array
+    {
+        $parts = explode(self::HIS_CODE_DELIMITER, $hisCode);
+        $map = [
+            DegreeProgram::DEGREE => $parts[0] ?? null,
+            DegreeProgram::AREA_OF_STUDY => $parts[1] ?? null,
+            DegreeProgram::LOCATION => $parts[6] ?? null,
+        ];
+
+        return array_filter($map, fn($value) => !is_null($value));
+    }
 }
diff --git a/src/Infrastructure/Repository/WpQueryArgsBuilder.php b/src/Infrastructure/Repository/WpQueryArgsBuilder.php
index 4fe1d87..8f3f41d 100644
--- a/src/Infrastructure/Repository/WpQueryArgsBuilder.php
+++ b/src/Infrastructure/Repository/WpQueryArgsBuilder.php
@@ -107,13 +107,7 @@ public function applyHisCodes(array $hisCodes, WpQueryArgs $queryArgs): WpQueryA
                 'relation' => 'AND',
             ];
 
-            try {
-                $taxonomyToTermMapping = $this->campoKeysRepository->taxonomyToTermsMapFromCampoKeys(
-                    CampoKeys::fromHisCode($hisCode)
-                );
-            } catch (RuntimeException) {
-                continue;
-            }
+            $taxonomyToTermMapping = $this->campoKeysRepository->taxonomyToTermsMapFromHisCode($hisCode);
 
             if (count($taxonomyToTermMapping) === 0) {
                 continue;