Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
What are the two most common hyperparameter tuning algorithms used in machine learning?

### Response:
The two most common hyperparameter tuning algorithms used in machine learning are grid search and random search. Grid search approaches require selecting a set of values for each hyperparameter, while random search explores a pre-defined range of values for each hyperparameter of interest.