The rhysida ransomware group listed Cheyenne & Arapaho Tribes on its data leak site on 2026-02-17. Country: US Sector: Government & Defense Domains named: cheyenneandarapaho-nsn.gov Claim as published on the leak site: Cheyenne & Arapaho Tribes The Cheyenne and Arapaho Tribes are a federally recognized united nation of two distinct peoples-the Tsistsistas (Cheyenne) and Hinono'ei (Arapaho)-with a historic alliance formed in the early 19th century.