I'm not sure why one of Trump's business ventures from long before the Presidency is even relevant here.
It just came up again because he and his son in law met with the bank's president in December and didn't disclose it. Kushner has been called to testify on the matter. Also, adds to the asinine constant denials from Trump he has zero involvement or interest in Russia. As pointed out in another post, it is stupid to deny it when it is documented and was something he and his businesses bragged about and disclosed before it became an election issue.
All part of that tangled web they have woven.