curl --request GET \
  --url https://api.kinsta.com/v2/sites/{site_id}/usage/cdn-bandwidth/this-month \
  --header 'Authorization: Bearer <token>'

{
  "site": {
    "id": "54fb80af-576c-4fdc-ba4f-b596c83f15a1",
    "this_month_cdn_usage": {
      "bandwidth": 100
    }
  }
}