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

{
  "registrants": 123,
  "eventOrganizer": "<string>",
  "eventUrl": "<string>",
  "attendees": 123,
  "appInfo": {
    "name": "<string>",
    "id": "<string>"
  },
  "eventType": "<string>",
  "eventCompleted": true,
  "endDateTime": "2023-11-07T05:31:56Z",
  "noShows": 123,
  "cancellations": 123,
  "createdAt": "2023-11-07T05:31:56Z",
  "startDateTime": "2023-11-07T05:31:56Z",
  "customProperties": [
    {
      "name": "<string>",
      "value": "<string>"
    }
  ],
  "eventCancelled": true,
  "externalEventId": "<string>",
  "eventStatus": "<string>",
  "eventDescription": "<string>",
  "eventName": "<string>",
  "objectId": "<string>",
  "updatedAt": "2023-11-07T05:31:56Z"
}