If you just want to see contents of session, try dd():
dd(session()->all());
If not, just use this to get all info:
$data = session()->all();
//set session
Session::put('sessionName', 'message');
//get session
Session::get('sessionName');
//don't forget to use "use IlluminateSupportFacadesSession;"
$data = $request->session()->all();
$request->session()->get('key', 'default');
$request->session()->all();
$request->session()->get('key');