Undefined variable: _SESSION in Laravel 5.2

use DB;
use URL;
use Session;
use Illuminate\Support\Facades\Input;
use Illuminate\Http\Request;

class OrderController extends Controller
{

   public function add_order(Request $req)
   {

// Iam tring to get this session varible data to insert it into database table

       $selected_deal = $_SESSION['selected_deal'];

// But give me this error " Undefined variable: _SESSION "

       $destination = $req->input('destination');
       $halal_products = $req->input('halal_products');
       $allergy1 = $req->input('allergy1');

via Chebli Mohamed