Why does it say "v'Gam"?
Targum Yonasan: Also [this evil was in the land].
Malbim: The Kena'anim also had Kadesh among them. 1
What is "Kadesh"?
Rashi: It is adultery.
Radak citing Targum Yonasan: It is [women] who go outside (harlots). Yonason translates so also below "va'Ya'aver ha'Kedeshim" (15:12).
Ralbag: It is homosexuality.
Why is there the prefix Hei in "ha'To'evos"? It is Samuch to "ha'Goyim"!
Radak: We find like this, e.g. "ha'Mizbe'ach Beis Kel" (Melachim II, 23:17) and other verses.
Malbim #1: It is not Samuch! They did like these To'evos, i.e. ha'Goyim
Indeed, sometimes a word is omitted from a verse. However, there are other difficulties. (a) It is abnormal for the verse to put the predicate before the subject. (b) Until now, the verse discussed sins of Yisrael. How can v'Gam refer to Kena'anim, who are mentioned only later? (c) "Ha'Goyim Asher Horish" were dispossessed! If the verse discusses their remnants, it should specify so! (PF)