Albert Barnes Commentary 2 Kings 18:1

"Now it came to pass in the third year of Hoshea son of Elah king of Israel, that Hezekiah the son of Ahaz king of Judah began to reign." — 2 Kings 18:1 (ASV)

In the third year - If Hoshea ascended the throne toward the close of the 12th year of Ahaz (2 Kings 17:1), and if Ahaz reigned not much more than 15 years (2 Kings 16:2), the first year of Hezekiah might synchronize in part with Hoshea’s third year.

Hezekiah - The name given by our translators follows the Greek form, Ἐζεκίας Ezekias, rather than the Hebrew, which is Hizkiah. Its meaning is “strength of Yahweh.”