curl --request GET \
  --url https://api.hubapi.com/marketing/v3/campaigns \
  --header 'Authorization: Bearer <token>'

{
  "results": [
    {
      "businessUnits": [
        {
          "id": 123
        }
      ],
      "createdAt": "2023-11-07T05:31:56Z",
      "id": "<string>",
      "properties": {},
      "updatedAt": "2023-11-07T05:31:56Z"
    }
  ],
  "total": 123,
  "paging": {
    "next": {
      "after": "<string>",
      "link": "<string>"
    },
    "prev": {
      "before": "<string>",
      "link": "<string>"
    }
  }
}