How can I filter posts by multiple categories and tags?

Excellent question, Rakesh. I don't think anyone has asked that particular question on this forum until now. I know the Display Posts plugin by our good friend, Bill Erickson, provides a method for showing posts that contain a list of categories or tags. And other people have solved this problem through the use of some custom code. But you can also simply create a link that contains a list of tags like this: https://example.com/tag/blue+green You'd have to manually add that link to a widget or navigation menu, so it's not as flexible as allowing your visitors to select multiple tags from a tag cloud, for example. But it is another method for showing posts that contain more than one tag. And of course, you could always hire one of the experts at Codeable to write some custom code for you at a relatively inexpensive rate. Hopefully, one of these methods will work for you. I'd be curious to learn which plugin or solution you wind up using!