When chaining Celery tasks, choose the correct signature method: - Use `.s()` when a task needs the output from the previous task in the chain - Use `.si()` (immutable signature) when a task doesn't need any output from the previous task Incorrect signature methods can cause task failures or unexpected data flow between tasks. ```python # Example of proper signature method usage: chain( initial_task.si(param1=value1), # First task or doesn't need previous output process_results.s(), # Needs output from initial_task save_to_database.si(param2=value2) # Independent task with static parameters ) ```