A life insurance policy pays in the event of a death. Those death proceeds are usually not subject to income tax.
However, they are most certainly subject to estate taxes.
One way your agent may recommend for consideration is a cross-purchase. The wife will own a policy on the husband; the husband will own a policy on the wife.
In the event of a death, the proceeds may be paid without being subject to income taxes or estate taxes.
Your agent, your CPA, or your attorney can inform you of how to do this effectively. For example, you do not want the premium payment for the husband’s policy to be signed by the husband. Doing so could allow the IRS to disallow the estate tax exemption.
Proper prior planning prevents pathetically poor performance.