Tirhakah was the king of Cush during the time of Sennacherib of Assyria and Hezekiah (King of Judah). He was destroyed by Sennacherib.
Isa 37:8When the king of Assyria heard that Rabshakeh had left Lachish, he returned and found the king fighting against Libnah.Isa 37:9Now the king of Assyria heard concerning Tirhakah king of Cush, “He has set out to fight against you.” When he heard it, he sent messengers to Hezekiah, saying,Isa 37:10“Thus shall you speak to Hezekiah king of Judah: ‘Do not let your God in whom you trust deceive you by promising that Jerusalem will not be given into the hand of the king of Assyria.
2 Kings 19:8Rabshakeh returned and found the king of Assyria fighting against Libnah, for he had heard that the king had left Lachish.2 Kings 19:9Now the king of Assyria heard concerning Tirhakah king of Cush, “He has set out to fight against you.” And he sent messengers again to Hezekiah, saying,2 Kings 19:10“Thus shall you speak to Hezekiah king of Judah: ‘Do not let your God in whom you trust deceive you by promising that Jerusalem will not be given into the hand of the king of Assyria.