When developing Craft CMS you might want to place a Matrix field inside a Matrix field. One of the better ways to achieve this is to install the SuperTable plugin by Verbb. The problem is that the documentation on how to query SuperTable fields isn't great - full of owner, ownerID, fieldID queries.
But the good news it's much simpler than it appears. Here's how to do it:
{% set blocks = entry.nameOfYourMatrixField.all() %}
{% if blocks|length %}
{% for block in blocks %}
{% set superTableBlocks = block.nameOfTheSuperTableBlockInYourMatrixField.all() %}
{% if superTableBlocks|length %}
{% for superTableBlock in superTableBlocks %}
<p>{{ superTableBlock.nameOfTheSuperTableField }}</p>
{{ superTableBlock.includedItemDescription }}
{% endfor %}
{% endif %}
{% endear %}
{% endif %}