Serialization converts an in-memory object, such as a trained model, into a sequence of bytes that can be stored in a file and reloaded later. It separates training from using the model. Loading a serialized file from an unknown source is risky, because some formats (pickle, joblib) can execute code.
Example
import joblib
joblib.dump(pipeline, 'model.joblib')
model = joblib.load('model.joblib')