Did you read where the signees must ensure the ILO is recognized by their laws? This implies that country laws must be changed to come in accordance to the ILO.
The Parties reaffirm their obligations as members of the International Labor Organization (ILO) and their commitments under the ILO Declaration on Fundamental Principles and Rights at Work and its Follow-Up (1998) (ILO Declaration).1 Each Party shall strive to ensure that
such labor principles and the internationally recognized labor rights set forth in Article 16.8 are
recognized and protected by its law.
That's an agreement to strive to do what each of the countries has already agreed to do in the past. It doesn't change any law.