<?php
$bdd = new PDO('mysql:host=localhost;dbname=ticket;charset:utf8', 'root', '');

$update = $bdd->query("UPDATE pannes SET traitement = " .$_POST['is_checked'] ." WHERE ID = " .$_POST['id']);

$traitement = $bdd->query("SELECT traitement FROM pannes WHERE ID=" .$_POST['id']);
$res = $traitement->fetch()['traitement'];
echo $res;
?>