You can create database links to Oracle Big Data Service from Autonomous Database.

Big Data Service provides enterprise-grade Hadoop as a service, with end-to-end security, high performance, and ease of management and upgradeability. After deploying the Oracle Cloud SQL Query Server to Big Data Service, you can easily query data available on Hadoop clusters at scale from Autonomous Database using SQL. This allows you to blend data coming from your data lake with data in your Autonomous Database.

Oracle Cloud SQL Query Server is an Oracle SQL engine that can be accessed using database links in Autonomous Database. You create links to Big Data Service using DBMS_CLOUD_ADMIN.CREATE_DATABASE_LINK. See Integrating Cloud SQL with Autonomous Database for more information.