A company wants to grant users in one AWS account access to resources in another...

IAM roles are a way to delegate access to resources in different AWS accounts. IAM roles allow users to assume a set of permissions for a limited time without having to create or share long-term credentials. IAM roles can be used to grant cross-account access by creating a trust relationship between the accounts and specifying the permissions that the role can perform. Users can then switch to the role and access the resources in the other account using temporary security credentials provided by the role. References: Cross account resource access in IAM, IAM tutorial: Delegate access across AWS accounts using IAM roles, How to Enable Cross-Account Access to the AWS Management Console