Yet, Danny Sullivan, from Search Engine Land, claims that he found one giant search engine that actually does use the tag. The funny twist is that the tag is used to identify spammers. Bing uses the META keyword tag as a "signal" that something is wrong on a website--it is kind of a red flag. Granted, Bing doesn't base their decision on the keyword tag alone...quite the opposite. They use about 1000 indicators to determine the spamminess of content. Just to be abundantly clear, Bing is not uses the tag as a ranking signal.
REFERENCE website: https://searchengineland.com/the-meta-keywords-tag-lives-at-bing-why-only-spammers-should-use-it-96874?utm_source=feedburner&utm_medium=feed&utm_campaign=feed-main