[Answered ]-How to filter an item in one queryset from appearing in another queryset in django

You will have to change your code to something like this using values_list to get only the pks in a list. Otherwise you are trying to compare a list of Post objects the exclude code

top_posts = Post.objects.all()[:4]
top_post_pks = top_posts.values_list('pk', flat=True)
politics_posts = Post.objects.filter(category='news').exclude(pk__in=top_post_pks)
...

Also maybe you need to do category=politics. In the question you have put category=news