--like many blood cancers, can cause neuropathy due to the cross-reactivity of the rogue antibodies with components of peripheral nerve.

If one gets good treatment for this, though, and stops or at least greatly lessens the antibody load, the nerves can have a chance to heal, with good nutrition and good vascular flow, the latter being helped by exercise.

People with blood cancers often get a double neuropathy whammy--the autoimmune factors associated with the cancer can cause neuropathy, and THEN a lot of the immune-modulating treatments also have a tendency to be neurotoxic (although, fortunately, most don't seem to be as neurotoxic as the heavy metal based drugs like cisplatinum that are used for some cancers and which are notoriously mitochondrial-damaging). The mechanisms are different--autoimmune attack versus direct introduction of chemicals toxic to many cells, including nerves--but I would imagine that anything that helps support the nutritive and respiratory functioning of the nerves, including exercise to tolerance, can only help (though the degree of help can of course vary widely, depending on how global the percipitating factors are).