MATLAB has the multibandread function when allows a user to open an ISIS .cub file as a matrix. Is there an equivalent function/library in Python for opening/manipulating ISIS .cub files?
Since GDAL has decent support for ISIS .cub files, I would recommend using rasterio. GDAL has it’s own Python methods but rasterio can be a little more pythonic. For some simple examples see: Reading raster files with Rasterio — Intro to Python GIS CSC documentation