Try this:

Get-ADPrincipalGroupMembership -Identity $env:username | Select name
Get-ADPrincipalGroupMembership -Identity 'username' | Select name

May need to install a module:

Install-WindowsFeature RSAT-AD-PowerShell

Also, try this:

get-aduser $env:username -Properties memberof | select -expand memberof
get-aduser 'username' -Properties memberof | select -expand memberof

Or, a module-free version:

(New-Object System.DirectoryServices.DirectorySearcher("(&(objectCategory=User)(samAccountName=$($env:username)))")).FindOne().GetDirectoryEntry().memberOf