It was a TV show made in China. Basically, two guys went back in time to the Qin dynasty. One of them had good luck and became the brother of a famous general, but the other one became a eunuch. In the end, both of them had immortality pills and lived till the modern age. That's all I remember. Does anyone know the title?
The Myth (2010) - https://mydramalist.com/3672-the-myth-2010 Is it this one? I haven't seen it, but it's the closest one I could find. It's remake(?) of an even older Jackie Chan movie.