[On Monday, Donald Trump Jr. said on Twitter that it was hardly unusual to take information on an opponent.]
From an American?  Sure.  From a foreign government(not to mention adversarial government that had been heavily sanctioned by the previous administration)?  That is not only highly unusual but illegal under federal law.  11 CFR 110.20 prohibits any direct or _indirect_ contributions or donations by foreign nationals to a campaign.  Contributions include (IIRC the latest election case was Citizens United) advertising, time campaigning, etc.