I’m currently on long term disability through Manulife and they’ve asked me if I have applied for CPP disability is there any benefit with applying for CPP will I gain or loose any income through that?

Any CPP Disability I come you receive will be credited to the insurer so you won’t get more income if you’re approved for CPP Disability. But if you don’t apply they may estimate how much you should get and deduct that amount from what you are getting by way of LTD so you should apply.