Is there any relation to copd and diabetes related to neurapthy which restricts exercise?

Yes and no: Diabetes is a well known cause of neuropathy that may restrict your exercise tolerance and participation. COPD is not a primary cause of neuropathy, but definitely tells on exercise tolerance and participation.

Possibly: Maintaining good exercise and endurance is important in copd. If you can't exercise from diabetic neuropathy, that might make it more difficult.

See below: Diabetes can give you a neuropathy that restricts exercise but that may be treatable. Exercise is good for copd. COPD if related to smoking can also be related to bad circulation which also limits exercise. Talk to your doctors!

Sure.: If I understand the question correctly, COPD limits exercise by making you short of breath more easily and diabetic neuropathy restricts exercise through causing leg pains which compromise mobility in general.