If you want to send a Ticket requester to slack as a lead you could do that simply by setting up an Extension and a Trigger.
Retrieve an API key from your Hubspot account. Please refer Hubspot documentation to see how this can be done.
You should now have an HubSpot API key which looks like that:
Create a new HTTP extension in your Zendesk account.
- Title - choose one, for example HUBSPOT_CONTACT
- URL - https://api.hubapi.com/contacts/v1/contact/?hapikey=
- Method - POST
- Content type - JSON
- Create a new trigger or use an existing one containing your conditions
- i.e. form = sales inquiry, ticket is created
- Add action "Notify target"
- select your previously created "Extension"
- provide the values for Hubspot fields which you want to be inserted within the contact
- use Zendesk placeholders here to input data from the ticket which has been created.