curl --request POST \
  --url https://api.lemlist.com/api/campaigns/{campaignId}/leads/{leadIdOrEmail}/interested \
  --header 'Authorization: Basic <encoded-value>'

{
  "firstName": "John",
  "lastName": "Doe",
  "companyName": "Acme Inc",
  "jobTitle": "Growth Engineer",
  "companyDomain": "example.com",
  "email": "support@lemlist.com",
  "preferredContactMethod": "email",
  "industry": "Technology",
  "Company name": "John Doe",
  "_id": "lea_fiDpiGV585wy3Oii2",
  "isPaused": false,
  "campaignId": "cam_bSn8EORHQxbWPjHvu",
  "contactId": "ctc_xW8Ou6C03Csv8vatp",
  "emailStatus": "deliverable"
}