Using "array_values" with "foreach" data?

Using "array_values" with "foreach" data?

I am trying to organize an array of data to be sent in an email. I have no
problem getting the data, but I am not sure how to organize it.
Foreach: Here outputs a list of questions generated by the user in the
backend
$message = array();
foreach($questions['questions'] as $key => $value){
if(is_array($value) && isset($value[ 'questionlist'])){
foreach($value as $key => $subquestion){ //line 119
foreach ($subquestion as $key => $value){
$message[] = $value['a-question'];
}
}
}
}
I am trying to conjoin the data with each other, the data from the foreach
and the $_POST data which is check values.
My logic for doing it this way is because one comes from the database, one
is just form data (that does not need to be saved to the database it comes
from the front end unlike the data from the database that is generated via
backend) That said there perhaps is a better way, but I pretty much got
this I am just not sure how to join the data so it looks like
<li>MYARRAYDATA - MYFORMDATA</li>
<li>MYARRAYDATA - MYFORMDATA</li>
<li>MYARRAYDATA - MYFORMDATA</li>
//The form input data '0', '1' values
$checks = $_POST['personalization_result'];
//Putting that data into array_values
$checkValues = array_values($checks);
//Then passing the array_values into 'implode' and organizing it with
a list (<li>)
$checkString = '<li>'.implode('</li><li>',$checkValues).'</li>';
//Then testing with var_dump outputs a nice list of '0','1' values
var_dump ($checkString);
Trying the same method but trying to conjoin the foreach array and the
check values does not work, here is an example.
//Similar to $checkValues I pass the data from the foreach into
"array_values"
var_dumping this works fine.
$arrayValues = array_values($message);
//This is obvious it's the same as above it "implodes" the data nicely
into a list(<li>)
$arrayString = '<li>'.implode('</li><li>',$arrayValues).'</li>';
//This var dumps the "$arrayString" nicely
var_dump ($arrayString)
Again the actual question is here, how do I conjoin each piece of data?
My Attempts: Here are my attempts for "conjoining" the data.
// This does not work well (maybe by cleaning up it can work) but it
outputs 2 separate lists
var_dump ($arrayString.'_'.$checkString);
//I tried to run it inside one implode variable this is invalid arguments
$checkString =
'<li>'.implode('</li><li>',$arrayValues.'_'.$checkValues).'</li>';
//Modified one implode variable this outputs see below
$checkString =
'<li>'.implode('</li>'.$arrayValues.'<li>',$checkValues).'</li>';
<li>Array
1</li>
<li>Array
0</li>
<li>Array
1</li>
<li>Array
0</li>