7 Even as Sodom and Gomorrah, and the cities around them, having, in the same way as these, given themselves over to sexual immorality and gone after strange flesh, are shown as an example, suffering the punishment of eternal fire.
Two cities are used as examples of what happens when it gives in to homosexuality. God’s righteous judgment gets poured out on them which causes their death and their sentence is to be an eternal place of fire.
The angels mentioned here are in reference to Genesis 6 when they left their positions that God assigned to them and caused humanity to become extremely evil through union with women. These fallen angels are to be distinguished from the ones who rebelled with Satan in the beginning. To this day, these fallen angels are chained up in a deep section in hell.