1) I am able to successfully authenticate with the external system, however, I am unable to parse the data to Visualforce page.

2) I get no output on the VF page. What is wrong with the below code?

if(response.getStatusCode()==200)
        {
            Map<String,Object> results= (Map<String,Object>)JSON.deserializeUntyped(response.getBody());                   
            user_id=String.valueOf(results.get('user_id'));
            team_id=String.valueOf(results.get('team_id'));
else
        {
            ApexPages.Message myMsg=new ApexPages.Message(ApexPages.Severity.ERROR, 'There was an error in fetching the data');
            ApexPages.addMessage(myMsg);