Vance had long known Thiel before he entered politics. He was Thiel's protègé back when he was working in Silicon Valley. In fact, he's been thick as theives with the tech-billionaire since he was attending Yale University. Thiel essentially bought Vance's election to Congress.

https://www.theguardian.com/technology/article/2024/jul/19/jd-vance-trump-vp-pick-silicon-valley