How can I run two AJAX requests simultaneously in WordPress?

Eureka! So I ended up just adding in a second ajax call into the function. For some reason it’s returning successful but not with a 200 response. Anyway, it’s working. If anyone knows why it’s returning an unknown response (besides 200 or 201) please share. Thanks!

function get_posts($params) {
    $.ajax({
        url: psc.ajax_url,
        data: {
            action: 'get_subcats',
            nonce: psc.nonce,
            params: $params
        },
        type: 'post',
        dataType: 'json',
        success: function(data, textStatus, XMLHttpRequest) {
            if (data.status === 200) {
            }
            else if (data.status === 201) {
                alert('201');
                $content.html(data.message);    
            }
            else {
                $('#subcategories').empty();
                $('#subcategories').append(data.content);
            }
        },
        error: function(MLHttpRequest, textStatus, errorThrown) {
            $status.html(textStatus);
        }
        });

        $.ajax({
        url: psc.ajax_url,
        data: {
            action: 'filter_posts',
            nonce: psc.nonce,
            params: $params
        },
        type: 'post',
        dataType: 'json',
        success: function(data, textStatus, XMLHttpRequest) {
            if (data.status === 200) {
                $('#ajaxPosts').html(data.content);
            }
            else if (data.status === 201) {
                $content.html(data.message);    
            }
            else {
                $status.html(data.message);
            }
        },
        error: function(MLHttpRequest, textStatus, errorThrown) {
            $status.html(textStatus);
        }
    });
}

functions.php

function psc_subcategories() {
if( !isset( $_POST['nonce'] ) || !wp_verify_nonce( $_POST['nonce'], 'psc' ) )
die('Permission denied');

$value = intval($_POST['params']['value']);;

ob_start();

$categories=  get_categories('child_of=".$value."&hide_empty=1');
      foreach ($categories as $cat) {
        $option .= '<option value="'.$cat->term_id.'">';
        $option .= $cat->cat_name;
        $option .= ' ('.$cat->category_count.')';
        $option .= '</option>';
      }
    echo '<option value="-1" selected="selected">Subcategory</option>'.$option;

$response['content'] = ob_get_clean();

die(json_encode($response));

}