curl --request GET \
  --url https://api.hubapi.com/marketing/v3/campaigns/{campaignGuid}/reports/contacts/{contactType} \
  --header 'Authorization: Bearer <token>'

{
  "results": [
    {
      "id": "<string>"
    }
  ],
  "paging": {
    "next": {
      "after": "<string>",
      "link": "<string>"
    }
  }
}