Can't get token replacement to work
You need to set the new value on the body, and save it.

function MYMODULE_node_presave(Drupal\Core\Entity\EntityInterface $node) {
  if ($node-&gt;bundle() == 'article') {
    $body = $node-&gt;get('body')-&gt;value;
    $token = Drupal::token();
    $body = $token-&gt;replace($body);
    $node-&gt;get('body')-&gt;value = $body;
    $node-&gt;save();
  }
}