2019 jw convention new song
You're referring to the new song performed at the 2019 Jehovah's Witnesses International Convention!
The song is titled "Rejoice the Lord Is King" (also known as "Rejoice, the Lord Is King" in some publications). It was written by Nathan Nockels, Daniel Carson, and Matt Maher, and was premiered at the convention held in Detroit, Michigan, USA, from June 27 to July 7, 2019.
The song is a joyful expression of praise and worship, celebrating the sovereignty and majesty of God. The lyrics are based on Psalm 97:1, which says: "The Lord reigns, let the earth rejoice; let the many coastlands be glad!"
The song has since been included in the Jehovah's Witnesses' official songbook, "Sing Out Joyfully to Jehovah," and is widely sung by Jehovah's Witnesses around the world.