Some strange logic there, yes Schiff has mention Biden many times but only in the context that Trump abused his power in order for Ukraine to announce an investigation into Biden.
But I understand where you are coming from you think Biden maybe guilty of some think and want it exposed, however this trial is about Trump not Biden. And if you are thinking in legitimises Trump's attempt to have Ukriane annouce an investigation, that is just silly.
If Trump was genuine in the idea that the Biden's should be investigated he has a swag of intelligence agencies at his disposal to do that and why would you seek a public announcement of a pending investigation before it starts? That would only tip off the person who is going to be investigated and they would then start destroying evidence. Seriously
Simple logic, would Biden testifying make any difference for the purposes of this trial? would it help find Trump innocent or guilty of abusing his power or obstructing congress? The answer is no, he is not relevant to the charges against Trump
