Laravel bootstrap colors different from CDN

My laravel bootstrap colors are much lighter, also th by default is not bold and some other small differences once included in my layout as:

 <link href="{{asset('css/app.css')}}" rel="stylesheet">

It is good while using this:

<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous">

Where should I look for the error?