Crossfire Hurricane is the name the FBI gave its investigation of Team Trump. That investigation committed 17 major errors and omissions according to a report by the Inspector General for the Department of Justice.
The FBI and the Department of Justice used political opposition research paid for by the Clinton campaign as the basis for obtaining search warrants from the Foreign Intelligence Surveillance Court. The information was assembled by former British spy Christopher Steele. His dossier of dirt on the Trump campaign alleged that Carter Page, a foreign policy advisor for the campaign, was an intermediary between the Campaign and the Russian government in a "well developed conspiracy" to help defeat Hillary Clinton in the 2016 election.
The problem is that the information in the dossier had never been corroborated, not by Steele, his main sources, the FBI or the Justice Department. Yet lawyers and top officials of both the FBI and Department of Justice told the Foreign Intelligence Surveillance Court that the information about Carter Page in the dossier was verified, true and correct. It wasn't.
Based on the the legal assurances of both the FBI and the Department of Justice, the FISA Court issued four search warrants over a nine month time period. All four FISAs were fraudulent because they were based on the phony dossier, direct lies to the court as well as lies of omission committed by agents and government lawyers at the FBI and the Department of Justice.
One of the most important resources to understanding "Spygate" is a report by the Department of Justice Inspector General. It was issued in December, 2019. SpyGate Truth repeatedly refers to it, citing page numbers for the source information we report. You can look for yourself. Here's a link to the full report. Be advised, however, it's 474 pages long and does not read like a spy novel.