The query should look like this, I’ve separated the arguments from the function so that they are easier to see.
$args = array(
'post_type' => 'events',
'posts_per_page' => -1,
'meta_query' => array(
array(
'key' => 'signature_event',
'value' => 'signature_event',
'compare' => '==' // not really needed, this is the default
)
)
);
$the_query = new WP_Query($args);
if ($the_query->have_posts()) {
// This
// if( get_field('signature_event') )
// isn't needed since we did a query to only get ones
// with a true value
?>
<ul>
<?php
while ($the_query->have_posts()) {
$the_query->the_post();
?>
<li><a href="<?php page_link(); ?>"><?php the_title(); ?></a></li>
<?php
} // end while have posts
?>
</ul>
<?php
wp_reset_postdata();
} // end if have posts
