Do hyperparameters get trained?

[staniPetrox]

Hey gang,

If I give my lightning module a hyperparameter like this

class Decoder(pl.LightningModule):
    def __init__(self, model_encoder):
        super().__init__()
        self.model_encoder = model_encoder #NOTE: This is also a pl.LightningModule

will it be trained if I use it within the training loop? Or does it remain static?
And on a side note, how can I actually check which layers get trained?

Thanks in advance!