Security Assertion Markup Language (SAML) is a standard protocol used for securely exchanging authentication and authorization data between organizations. SAML allows you to use your existing identity provider (IdP) to authenticate users and grant them access to AWS resources.

Using SAML with AWS IAM allows you to use your existing identity provider to authenticate users and grant them access to AWS resources. This can be especially useful if you have a large number of users who need access to AWS resources, as it allows you to manage their access centrally. 

In the context of Amazon Web Services (AWS), SAML can be used to integrate with an external identity provider (IdP) to provide single sign-on (SSO) access to AWS resources. This can be useful for organizations that want to use their existing identity management systems to control access to AWS resources, hence allowing a user to use a single set of credentials to access multiple applications and services. 

With SAML and IAM, you can set up SSO for your users so that they can use their existing corporate credentials to access AWS resources. This can make it easier for users to access AWS resources, and it can also help you manage access to those resources more effectively. 

To set up SAML with AWS IAM, you will need to perform the following steps:
1. Set up an identity provider (IdP). This can be an on-premises IdP, such as Microsoft Active Directory, or a cloud-based IdP, such as Okta or OneLogin.
2. Configure your AWS account ( AWS Identity and Access Management (IAM) ) to trust the IdP. This involves creating an IAM identity provider in the AWS Management Console, and uploading the IdP's SAML metadata document to AWS. 
3. Once the IdP and IAM have been configured, you can use the IdP to authenticate users and grant them access to AWS resources. 
4. The IdP will issue a SAML assertion, which contains information about the user's identity and the permissions they have been granted. 
5. IAM will use this information to determine whether the user should be allowed to access the requested AWS resources. 
6. Create IAM roles for your users. These roles determine what resources the users can access and what actions they can perform on those resources. 

SAML integration with IAM is a convenient way to provide single sign-on access to AWS resources for users who are already authenticated with an external identity provider. It can also be useful for organizations that want to use their existing identity management systems to control access to AWS resources.