AWS CognitoID VS AWS Session Token

I'm a bit confused about the difference between an AWS session token and an AWS CognitoID, are they they same? because through this code

AWSCognitoCredentialsProvider *credentialsProvider = [[AWSCognitoCredentialsProvider alloc]
                                                      initWithRegionType:AWSRegionUSEast1
                                                      identityPoolId:@"my-identity-pool"];

AWSServiceConfiguration *configuration = [[AWSServiceConfiguration alloc] initWithRegion:AWSRegionUSUnknown credentialsProvider:credentialsProvider];

[AWSServiceManager defaultServiceManager].defaultServiceConfiguration = configuration;

[[credentialsProvider getIdentityId] continueWithBlock:^id(AWSTask *task) {

    if (task.error) {
        NSLog(@"Error: %@", task.error);
    }
    else {
        // the task result will contain the identity id
        NSString *cognitoId = task.result;
       // -------------------Outputs cognito Id------------------------
        NSLog(@"%@,", task.result);

    }
    return nil;
}];

task.result gives back an AWS CognitoID but what about an AWS Session Token? How can I get it from my ios?