In this chapter, Caleb asks Joshua to give him Hebron as his inheritance in the land.
After reading this chapter, I'm pretty sure this chapter is happening out of order with the story that was in Joshua 1-11. First, v. 6 says that Caleb approached Joshua when they were in Gilgal, which is where Israel camped before attacking Jericho in Joshua 6. It is unlikely the army returned to Gilgal after that because they had to conquer all those cities in the north and south. Second, Hebron was one of the cities that was captured in Joshua 10, so when Caleb is saying that he will "drive them out" in v. 12, it wouldn't really make sense to say that after the city had already been captured.
It's possible there were towns in the countryside around Hebron that hadn't been captured, but I think that's unlikely because of the importance of city walls that I have brought up before. Hebron would have been the best defended city, so with it being captured the surrounding area would be exceedingly vulnerable and every time the Israelites have conquered a city before they killed all of the inhabitants, and I see no reason they would be less thorough here.
Other than the timing, this chapter contains a brief recapitulation of Caleb's history, reminding us how he was a spy who entered Canaan in Num 13, and interestingly, Caleb specifically requests for his inheritance the land that they spied out. In Num 13, it says the spies passed up through the Negev (the southern desert of Israel) into the hill country and they came near Hebron. So Caleb is indeed requesting the land they spied out before the first generation rebelled and were condemned to die in the desert. He does so in an ironic way, recalling the Anakim and "great walled cities" that caused the other spies to give a bad report. So Caleb highlights the fierce resistance they can expect in this region, and his own determination that if "the LORD will be with me", they will be able to conquer everyone who resists them. As we were told in Joshua 10, the Israelites were successful in this goal.
This chapter also reminds us that the Levites don't get a share of the land, but the two sons of Joseph get equal shares of the land, so it's basically just some math that there are still 12 shares of the land, with two for Joseph and none for Levi. I think I've talked about this before so I won't go into depth, but the OT loves talking about the "twelve tribes", but it's not always the same twelve. Sometimes the twelve includes "Joseph and Levi" and sometimes it includes "Ephraim and Manasseh". Its not an important point, but it can be confusing sometimes.