Believer says: The atheist worldview is inadequate, because it cannot explain what life is all about, but the Christian worldview can explain it.
But skeptic replies: Christians naturally assume that their biblical explanation is better than a secular one. Atheists may very well have a worldview, such as there’s no life beyond the present one, so make the most of life and, like the old expression, “seize the day.” But there’s really no general tenet for atheism, not even that one.
For example abiogenesis--meaning how life got started on earth--remains one of nature’s mysteries. Apologists may claim that God gave life its start. But beyond their faith assertion, the mystery lingers on. Naturally the fact of the matter is that humanity will always face unknowns.
Recap: The Christian worldview isn't testable, so there isn’t any way to show if it’s right.