There are many "Cosmological Arguments" for the existence of God, and they are all multiply flawed in both facts and logic. But all more or less follow a common script:
1. Every thing has either been caused to exist by something else or else exists uncaused.
2. Not every thing has been caused to exist by something else.
3. Therefore, at least one thing is itself uncaused.
4. That one thing must be God.
The leap from 3. to 4. is always a non sequitur. In every form of the Cosmological Argument, there has never been a valid logical step getting from "there is an uncaused cause" to "that cause is God" (especially where God means "a supernatural being with a vastly complex mind and amazingly convenient powers and attributes"). The steps up to 3. are logically valid, but 3. requires 2. to be factually true, and unfortunately we have no scientific evidence confirming it is true. Though we can confirm that the current observable universe had a beginning (the Big Bang), we cannot confirm that that beginning didn't have a cause, much less that that cause didn't have another cause, and so on down the line, such that nothing exists that does not have some prior cause.
Arguments against such an infinite series are always based on ignorance of the actual axioms of transfinite mathematics, which entail there is nothing logically impossible about such a series preceding the Big Bang. We just don't know. Therefore, we can't claim to know 2. is true. Therefore, we can't claim to know 3. is true. It might not be true. But even if 3. is true, such an uncaused cause can be anything, including a mindless originating event or a simple physical fact, and naturalism predicts that if there is such an uncaused cause, that is most probably the kind of cause it is.