Hello,
The addTable method, as other methods, allows adding WordFragments (https://www.phpdocx.com/documentation/practical/wordfragments-and-wordml) as contents.
You just need to create a new WordFragment, insert the HTML and then add the values to the table:
$html = new WordFragment($docx);
$html->embedHTML($htmlContent);
$valuesTable = array(
array(
'Title A',
'Title B',
'Title C',
),
array(
'Line A',
'Line B',
$html,
),
);
$docx->addTable($valuesTable);
You can see a full sample using WordFragments on the API page of the method (https://www.phpdocx.com/api-documentation/word-content/add-table-Word-document-with-PHP).
You can also add a placeholder to the table as value an then use replaceVariableByHTML or replaceVariableByWordFragment to replace it with a WordFragment of the HTML.
Regards.