Route::get('/{country}/{category}', ['as' => 'tour.list', 'uses' => 'LinkController@tourlist']);

Route::get('/{category}/{slug}',['as' => 'single.tour', 'uses' => 'LinkController@singleTour']);

public function tourlist($country, $category)
{
    $tour = Tour::whereHas('category', function($q) use($category) {
            $q->where('name','=', $category);
        })
        ->whereHas('country', function($r) use($country) {
            $r->where('name','=', $country);
        })
        ->get();
    return view('public.tours.list')->withTours($tour);
}
public function singleTour($slug,$category)
{
    $tour = Tour::where('slug','=', $slug)
              ->whereHas('category', function($r) use($category) {
            $r->where('name','=', $category);
        })
        ->first();
    return view('public.tours.show')->withTour($tour);
}

<a href="{{ route('single.tour',['category' => $tour->category->name, 'slug' => $tour->slug]) }}">{{$tour->title}}</a>