Render custom code when no content on Search results

Hello, can you share the filter which i should use to “Render custom code when no content on Search results” and for reference i will use on below code:

add_filter('blocksy_filter_hook', function ($content) {
    if ( is_search() ) {
        $content .= "
 
<center><b><h3 class='title'>Try below Google Search method as well.</h3></b></center>
 
<script async src=''></script>
<div class='gcse-search'></div>";
    }
 
    return $content;
});