このコードでこの問題を解決します
$query = Worker::select('workers.name_and_surname', 'workers.id', 'workers.location','company_saved_cv.worker_id')
->leftJoin('company_saved_cv', function($leftJoin)use($company_id)
{
$leftJoin->on('workers.id', '=', 'company_saved_cv.worker_id');
$leftJoin->on(DB::raw('company_saved_cv.company_id'), DB::raw('='),DB::raw("'".$company_id."'"));
})