In Genesis 4:16-24, we are given the lineage from Cain. This isn’t a full genealogy, with dates, like we see in Genesis 5. It’s more like a side-note. Genesis 5 covers the patriarchal line from Adam to Noah, through Seth. Cain is not part of that lineage.
No, this is more like telling us the family kept in touch for a few generations. We’re not told if all of the descendants of Cain were fully his progeny, or if his children (etc.) married some of Adam and Eve’s descendants from other lines.
We are given six descendants by name, with some minor information about a few of them. For example, Jubal was the father of all those who play the lyre and pipe.
But, wait: how can Jubal, who did not survive the Flood, be the father of ALL those who play lyre and pipe?
In my opinion, he seems to have been the guy who invented those instruments and figured out how to make them sound nice. Noah, for his part, probably included some household goods on the ark, such as musical instruments. So, technology seems likely to have been traded between Cain’s line and Seth’s line.
In verses 23-24 of chapter four, we find out that Lamech, the fifth in line from Cain, repeated his ancestor’s evil deed by killing a man. But, recall that Cain complained that his punishment was too great, an obvious ploy to get God to reduce the sentence (which He did).
But, Lamech is in-your-face about his crime. He’s basically saying if anybody tries to exact vengeance on him, he’ll avenge himself first, by killing the purposed avenger before he gets a chance to kill Lamech.
This guy was the first godfather! “Don’t cross me, or I’ll make you an offer you can’t refuse.”