The laundering claim comes from the fact that
150 transactions to either Hunter or Jim Biden were red flagged by the bank, by a person who's job it is to catch money laundering, for a variety reasons. One being
$3 million dollars from China for which there were
apparently no services or any loan documentation provided to justify the payment. That money was them quickly moved to other accounts and eventually some amount made it to Joe as, I believe, a "loan payment".
There's also the
document where Hunter claims to be paying Joe about $49k in rent while he was living in Joe's Delaware home. Those payments started 2 months after Joe left office. An amazing coincidence..... Nothing on Joe's publicly available tax returns reflects rent in that amount.
Now, politicians aren't dumb. They have lawyers who are skilled at making things appear legal on paper, so there is no smoking gun, per se.