“Variable universal life insurance” (VUL) is permanent life insurance with flexible premiums and an adjustable death benefit, where the cash value is invested in options the policyholder chooses, so its value rises or falls with their performance. Variable universal life is a US term. In Canada, the equivalent is universal life insurance with investment accounts that follow the options you choose.
As with other permanent life insurance, the cash value grows without annual tax only if the policy is an exempt policy under the Income Tax Regulations. Withdrawals and policy loans are dispositions, taxed on the amount above the adjusted cost basis. The death benefit is generally paid out tax-free to beneficiaries.