Here is the CDN

<script src="https://api.mapbox.com/mapbox-gl-js/v2.9.1/mapbox-gl.js"></script>
<link href="https://api.mapbox.com/mapbox-gl-js/v2.9.1/mapbox-gl.css" rel="stylesheet">

Now we can add a map code

<div id='map' style='width: 80%; height: 300px;'></div>
<script>
  mapboxgl.accessToken = 'YOUR_MAPBOX_ACCESS_TOKEN';
  var map = new mapboxgl.Map({
    container: 'map',
    style: 'mapbox://styles/mapbox/streets-v11'
  });
</script>

Result