Can a scammer hack my phone by calling me?

Can a scammer really hack into my phone just by making a call? I've heard rumors that they can access my personal information and steal my cryptocurrency holdings through my phone. Is this really possible, or is it just another scare tactic? I'm always cautious about sharing my personal details, but I'm not sure how secure my phone actually is. Could you please explain how a scammer might try to hack my phone through a call, and what steps I can take to protect myself?