Trump actually asked for that specifically. He wanted the hostages returned before he entered office. I don't know why when it would look way better for him if the deal happened while he's president.

But this deal was ultimately about Trump twisting Netanyahu's arm. Biden has been peddling this deal for like 8 months and Israel kept refusing, because they knew Biden would just keep sending them weapons and not punish them in any way. Trump must have said something different for what his term will be like. Biden taking credit is so disingenuous, but so is most of the Democratic party.