April 3, 2026For U.S. Positions: While subject to change based on business needs, Leidos reasonably anticipates that this job requisition will remain open for at least 3 days with an anticipated close date of no earlier than 3 days after the original posting date as listed above. The ISSE collaborates with multidisciplinary teams - including Information Systems Security Managers (ISSMs), software developers, systems engineers, and government stakeholders—to integrate effective security controls and ensure systems remain resilient against evolving threats and vulnerabilities.