The QuerySet value for an exact lookup must be limited to one result using slicing-Django

The following will work:

def newsDetailView(request, news_pk):
    news = get_object_or_404(News, id=news_pk)
    relative_news = News.objects.filter(tag__id__in=news.tag.all())

Generally this error occurs when we use model queryset at the place of django models object. In the given question you have done the same. "Objects.filter" returns the model query set there can be single or multiple django model objects, but "objects.get" returns single django model object. Or we can use .last() and .first() with "objects.filter".