So I think this is a good example of pipelines and data:
Basically Task A generates data stored using the cleamrl-data (See Dataset class). The output of that is an ID of the Dataset. Then Task B uses that ID to retrieve the Dataset created by Task A.
documentation
https://github.com/allegroai/clearml/blob/master/docs/datasets.md

Example:
Step A creating Dataset:
https://github.com/alguchg/clearml-demo/blob/main/process_dataset.py
Step B training model using the Dataset created in step A:
https://github.com/alguchg/clearml-demo/blob/main/sklearn_example.py