Many spam calls are scams, but some may be genuine marketing calls from insurance agents selling health insurance policies. If you sign up for one of these health insurance plans, you'll genuinely receive coverage from a policy provider.
On the other hand, you won't be covered if you sign up for a "plan" from a scammer. The health insurance plan they were "selling" you didn't actually exist, and they're not licensed health insurance agents. Instead, they are calling you to steal your money and/or identity.