'cmd' Field Definitions sysprocesses MS SQL Server
As suggested in comment sys.sysprocesses is deprecated and Microsoft does not recommends it to use further. Its just there for backward compatibility

The above view has been replaced by sys.dm_exec_requests. You would see cmd column from sys.sysprocesses is now command column in sys.dm_exec_requests and this column tells you 


  Identifies the current type of command that is being processed. Common
  command types include the following:
  
  • SELECT 
  
  • INSERT 
  
  • UPDATE 
  
  • DELETE 
  
  • BACKUP LOG 
  
  • BACKUP DATABASE
  
  • DBCC 
  
  • FOR 
  
  The text of the request can be retrieved by using sys.dm_exec_sql_text
  with the corresponding sql_handle for the request. Internal system
  processes set the command based on the type of task they perform.
  Tasks can include the following: • LOCK MONITOR
  
  • CHECKPOINTLAZY
  
  • WRITER
  
  Is not nullable.


Instead I suggest you to focus on column sql_handle which is present in sys.dm_exec_requests. Below code would give you query behind sql_handle

select er.session_id,
er.command,
t.text --gives query behind sql_handle
from sys.dm_exec_requests er
cross apply sys.dm_exec_sql_text(er.sql_handle) t