echo an SQL row for each using a checkbox and a submit button

I will simplify the code in order to highlight what I need:

<form id="highlighttable" name=form1 method="POST">
    
    <div class="form-group">
        <button name="save_multicheckbox" class="btn-primary">Save Checkbox</button>
    </div>
    <?php
      if(isset($_POST['save_multicheckbox'])){
        echo "<p>yes</p>";
        $checklist = $_POST['ckb'];
        foreach($checklist as $list) {
            echo "<p>as</p>";
        }
      }
    ?>
        <table>
        <tr id="col-title">
                    <th>Title</th>
                    <th>Type</th>
                    <th>Post Date</th>
                    <th>Url</th>
                    <th>Feature</th>
                </tr>

                <?php foreach($result as $res){
                        ?><tr>
                            <td><h6>Lorem</h6></td>
                            <td><h6>Lorem</h6></td>
                            <td><h6>Lorem</h6></td>
                            <td><h6>Lorem</h6></td>
                            <td id="h-center"><input type="checkbox" name="ckb[]" onclick="chkcontrol(<?php echo $res->chkbox_num; ?>)">
                                </td>
                            </tr>
                        <?php
                    } ?>
        </table>
 </form>

I have foreach from my select query, which outputs table rows below:

<?php foreach($result as $res){} ?>

output:

what I am trying to do is to echo or retrieve the rest of the columns on each selected row by marking what I want to get with a checkbox (last column)

<td id="h-center"><input type="checkbox" name="ckb" onclick="chkcontrol(<?php echo $res->chkbox_num; ?>)"></td>

my problem is that my foreach does not output the selected rows with that I tried below:

      if(isset($_POST['save_multicheckbox'])){
        echo "<p>yes</p>";
        $checklist = $_POST['ckb'];
        foreach($checklist as $list) {
            echo "<p>as</p>";
        }
      }

first I tried to add an echo inside the button to check if it works and it does, I am just wondering how to show the selected rows. Is there maybe an issue with the variable I am using to get it? my attempt is $checklist = $_POST['ckb']; where ckb is the name of the checkbox.