I keep getting a phone call that there is suspicious activity on my iCloud account is this a scam

It is a very common scam attempt.

Apple does not make such calls.

All such calls are scams from criminals attempting to steal your personal and financial information. The callers will often use number spoofing to pretend they are calling from a legitimate business. The correct course of action is to ignore the calls or hang up on them, repeatedly if needed. 

Avoid phishing emails, fake 'virus' alerts, phony support calls, and other scams - Apple Support

Yes. Apple only contacts people if they reach out first(posting on these boards counts.)

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