Google isn't using the keywords meta tag in your algorithm.

Other search engines can still be using this tag but Google simple ignore this information.

This is an old tag used in the past by Google to help the Web Crawler understand what are the 'topics' of your webpage.

If some user search for this specific 'topics' on Google, there is a good change of your website get listed in the search results. Over the time, Google improves your algorithm to be more intelligent, getting more information about your webpage with less meta tags.

One of the most important meta tags used by Google is the description tag.

This information is, in most cases, part of the snippet shown in the search results.