Ezekiel 37:22 And I will make them one nation in the land upon the mountains of Israel; and one king shall be king to them all: and they shall be no more two nations, neither shall they be divided into two kingdoms any more at all:
The nation of Israel was split into two kingdoms after the death of Solomon. The northern kingdom was taken into captivity by the Assyrians about 722 B.C. The southern kingdom was taken into captivity by the Babylonians about 586 B.C. After 70 years the southern kingdom was repatriated by Cyrus the king of Persia. The land was known as Judaea. They went back to the land without a king.
God had told Zedekiah:
Ezekiel 21:25-27 And thou, profane wicked prince of Israel, whose day is come, when iniquity shall have an end, 26 Thus saith the Lord GOD; Remove the diadem, and take off the crown: this shall not be the same: exalt him that is low, and abase him that is high. 27 I will overturn, overturn, overturn, it: and it shall be no more, until he come whose right it is; and I will give it him.
The Romans subsequently removed the Jews from the land (the second overturning).The nation was reformed in the land in 1948 and took the name Israel. Ezekiel prophesies that there will be a third overturning (chapters 38 and 39) prior to the return of Christ (he whose right it is). Israel will not have another king until Christ returns as their king.
Luke 1:32-33 He shall be great, and shall be called the Son of the Highest: and the Lord God shall give unto him the throne of his father David: 33 And he shall reign over the house of Jacob for ever; and of his kingdom there shall be no end.
At that time all the descendants of Jacob will return to the land and be settled in it as described in Ezekiel 48. In conclusion, Ezekiel is speaking of the future and Jesus is the king to whom he refers.
John 18:37 Pilate therefore said unto him, Art thou a king then? Jesus answered, Thou sayest that I am a king. To this end was I born, and for this cause came I into the world…
Matthew 27:37 And set up over his head his accusation written, THIS IS JESUS THE KING OF THE JEWS.
I hope you find this helpful.