https://es.mathworks.com/help/deeplearning/ref/nnet.cnn.layer.maxpooling3dlayer.html
MaxPooling3DLayer - 3-D max pooling layer - MATLAB
A 3-D max pooling layer performs downsampling by dividing three-dimensional input into cuboidal pooling regions, then computing the maximum of each region.
d maxpoolinglayermatlab