The person is John Cena, an actor. While promoting some film (probably in Taiwan) he said Taiwan is a country, then later apologized to the Chinese for that in Mandarin. This happened back in May 2021. Some MSM thought the apology was silly and satirized it by dubbing an over-the-top apology with statements like Taiwan doesn't even exist. (When I searched the first hits were the satire, not what Cena actually said.)
I don't know how the song's lyrics relate to Cena or Taiwan.
The video has made his name Xina. That may be part of the satire but it may also be the western alphabet (pinyin) version of how his name is written in Chinese characters in the Chinese press.
O...Kay. I remember reading about the actor who apologized to China for calling Taiwan...Taiwan. I guess he could have called it the Republic of China and really set off some fireballs. I didn't see pictures of the actor and, frankly, I wouldn't have known who he was anyway.