Microsoft Dynamics 365 Sales offers a robust customer relationship management system, enabling businesses to understand their customers' needs more accurately and secure more deals. To fetch opportunities from Microsoft Dynamics 365 Sales using Python, one must authenticate with the API using OAuth 2.0, which involves setting up an OAuth flow, directing users to an authorization URL, and exchanging an authorization code for an access token. Once authenticated, the access token can be used to make requests to the API, such as fetching opportunities, which returns a JSON response containing the opportunity data. Additionally, Merge's Unified API allows developers to build integrations with multiple CRM systems, including Microsoft Dynamics 365 Sales, Salesforce, and HubSpot, making it easier to cater to a diverse range of CRM tools used by clients. By building to Merge's CRM Unified API, developers can offer dozens of CRM integrations to clients, streamlining the integration process and reducing the time spent on individual API integrations.