--cnn_scoring determines where in the docking pipeline the CNN scoring function is applied. By default, it is used for re-scoring. The Figure 1 in the GNINA 1.0 paper for more details.

--scoring allows you to select which (classical) scoring function to use, for the steps of the docking pipeline where the CNN scoring function is not used.

Thank you for your answer. In scoring flag, there is the option "default" (ad4_scoring default dkoes_fast dkoes_scoring dkoes_scoring_old vina vinardo). Which scoring function is this?

Vina is the default scoring function, as described in the same paper mentioned above:

[...] the non-CNN scoring function, defaulting to the Vina scoring function.