Amazon AppStream 2.0 now offers Federal Information Processing Standard 140-2 (FIPS) compliant endpoints (FIPS endpoints) in all U.S. AWS Regions where AppStream 2.0 is available. FIPS 140-2 is a U.S. and Canadian government standard that specifies the security requirements for cryptographic modules that protect sensitive information. AppStream 2.0 FIPS endpoints use FIPS-compliant cryptographic standards, which may be required for certain sensitive information or regulated workloads.  

from Recent Announcements https://aws.amazon.com/about-aws/whats-new/2019/10/amazon-appstream-2-now-supports-fips-140-2-compliant-endpoints/