The men of Ephraim did not conquer the Canaanites living in Gezer. The Canaanites lived among them in Gezer.

the king of Eglon (one), the king of Gezer (one),

Solomon built up Gezer, lower Beth Horon,

David did just as God commanded him, and they struck down the Philistine army from Gibeon to Gezer.

Then King Horam of Gezer came up to help Lachish, but Joshua struck down him and his army ¹  until no survivors remained.

It then descended westward to Japhletite territory, as far as the territory of lower Beth Horon and Gezer, and ended at the sea.

The Ephraimites ¹  did not conquer the Canaanites living in Gezer. The Canaanites live among the Ephraimites to this very day and do hard labor as their servants.

They assigned them Shechem (a city of refuge for one who committed manslaughter) in the hill country of Ephraim, Gezer,

David did just as the Lord commanded him, and he struck down the Philistines from Gibeon all the way to Gezer. ¹ 

They were allotted as cities ¹  of refuge Shechem and its pasturelands (in the hill country of Ephraim), Gezer and its pasturelands,

Their property and settlements included Bethel ¹  and its surrounding towns, Naaran to the east, Gezer and its surrounding towns to the west, and Shechem and its surrounding towns as far as Ayyah and its surrounding towns.

Later there was a battle ¹  with the Philistines in Gezer. ²  At that time Sibbekai the Hushathite killed Sippai, ³  one of the descendants of the Rephaim, and the Philistines ⁴  were subdued.

Here are the details concerning the work crews ¹  King Solomon conscripted ²  to build the Lord’s temple, his palace, the terrace, the wall of Jerusalem, ³  and the cities of ⁴  Hazor, ⁵  Megiddo, ⁶  and Gezer.

(Pharaoh, king of Egypt, had attacked and captured Gezer. He burned it and killed the Canaanites who lived in the city. He gave it as a wedding present to his daughter, who had married Solomon.)