John wants to create a button on a custom CRM card that, when clicked, opens the standard HubSpot email composer pre-populated with subject and body content derived from card data (potentially via a serverless function).

Cameron recommends using the built-in `CrmActionButton` UI component with the 'Send a one-to-one email' action type (`SendEmailAction`). This component is specifically designed to open the email composer with pre-filled data and avoids the need for a custom button and serverless function for this specific task.