Case 还是Received,但是收到DHS邮件'We are still reviewing your case and there ...

邮件内容如下，我看了两个网站，都还是Received，这代表啥意思？
We are still reviewing your case and there are no updates at this time

We will notify you when your case status changes. We last took action on your case on November 26, 2018.