@darshan-majithiya had opened #15429 to add the hyperparameter tuning PR but it's gone stale. I'm adding this issue to see if they want to pick it back up, or if not, if someone wants to pick up where they left off in the spirit of open source 😄 
airflow/providers/google/cloud/operators/mlengine.py
"""
    Start a Google Cloud ML Engine prediction job.
    .. seealso::
        For more information on how to use this operator, take a look at the guide:
        :ref:`howto/operator:MLEngineStartBatchPredictionJobOperator`
    NOTE: For model origin, users should consider exactly one from the
    three options below:
    1. Populate ``uri`` field only, which should be a GCS location that
       points to a tensorflow savedModel directory.
    2. Populate ``model_name`` field only, which refers to an existing
       model, and the default version of the model will be used.
    3. Populate both ``model_name`` and ``version_name`` fields, which