In the case of both Athena and Glue, if you have some data and want to query upon that, then you can basically use Glue to get the schema and Athena to query the data. You need both of them to work.
Amazon Athena is an interactive query service that makes it easy to analyze data in Amazon S3 using standard SQL. Athena is serverless, so there is no infrastructure to manage, and you pay only for the queries that you run.