curl --request GET \
  --url https://api.example.com/api/Integrations/CampaignMonitor/Lists

{
  "clients": [
    {
      "clientID": "<string>",
      "name": "<string>"
    }
  ],
  "lists": [
    {
      "clientID": "<string>",
      "listID": "<string>",
      "name": "<string>"
    }
  ]
}