Hello @laurent_pourchot,
It is possible both to stack TF-DF “on top of existing” model (see intermediate colab 6) as well as to stack a model/set-of-operations (e.g. concatenate output) on top of a TF-DF (currently not demonstrated in a colab) using the Sequential or Functional Keras API. What’s important is that “fit” is called the TF-DF model.