CSS
<link rel="stylesheet" type="text/css" href="cdn.jsdelivr.net/npm/slick-carousel@1.8.1/slick/slick.css"/>
JS
<script type="text/javascript" src="cdn.jsdelivr.net/npm/slick-carousel@1.8.1/slick/slick.min.js"></script>
<link rel="stylesheet" type="text/css" href="//cdn.jsdelivr.net/npm/slick-carousel@1.8.1/slick/slick.css"/>
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap@4.6.1/dist/css/bootstrap.min.css" integrity="sha384-zCbKRCUGaJDkqS1kPbPd7TveP5iyJE0EjAuZQTgFLD2ylzuqKfdKlfG/eSrtxUkn" crossorigin="anonymous">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.6.0/jquery.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/bootstrap@4.6.1/dist/js/bootstrap.bundle.min.js" integrity="sha384-fQybjgWLrvvRgtW6bFlB7jaZrFsaBXjsOMm/tB9LTS58ONXgqbR9W8oWht/amnpF" crossorigin="anonymous"></script>
<script type="text/javascript" src="//cdn.jsdelivr.net/npm/slick-carousel@1.8.1/slick/slick.min.js"></script>
add latest version of slick slider
css
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/slick-carousel/1.8.1/slick.min.css" integrity="sha512-yHknP1/AwR+yx26cB1y0cjvQUMvEa2PFzt1c9LlS4pRQ5NOTZFWbhBig+X9G9eYW/8m0/4OXNx8pxJ6z57x0dw==" crossorigin="anonymous" />
js
<script src="https://cdnjs.cloudflare.com/ajax/libs/slick-carousel/1.8.1/slick.min.js" integrity="sha512-XtmMtDEcNz2j7ekrtHvOVR4iwwaD6o/FUJe6+Zq+HgcCsk3kj4uSQQR8weQ2QVj1o0Pk6PwYLohm206ZzNfubg==" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/slick-carousel/1.9.0/slick.min.js" integrity="sha512-HGOnQO9+SP1V92SrtZfjqxxtLmVzqZpjFFekvzZVWoiASSQgSr4cw9Kqd2+l8Llp4Gm0G8GIFJ4ddwZilcdb8A==" crossorigin="anonymous"></script>