you first set number of "?" in query and then by a "for" send parameters like this :
require 'dbConnect.php';
$db=new dbConnect();
$array=[];
array_push($array,'value1');
array_push($array,'value2');
$query="SELECT * FROM sites WHERE kind IN (";
foreach ($array as $field){
$query.="?,";
}
$query=substr($query,0,strlen($query)-1);
$query.=")";
$tbl=$db->connection->prepare($query);
for($i=1;$i<=count($array);$i++)
$tbl->bindParam($i,$array[$i-1],PDO::PARAM_STR);
$tbl->execute();
$row=$tbl->fetchAll(PDO::FETCH_OBJ);
var_dump($row);