Yes. Jesus says there is an unforgiveable sin. In Mark 3:29 he says, "But whoever blasphemes against the Holy Spirit never has forgiveness, but is guilty of an eternal sin."
But what exactly is it? In this case, the Pharisees heard Jesus’ teaching and saw Jesus’ miracles, and they were experts in the Scriptures which predicted his arrival, but when he came they not only rejected Jesus but said he was working with the power of Satan. So it was a whole-hearted rejection in response to an extraordinary amount of gracious revelation by God.
On the other hand, the Apostle Paul was a Pharisee who also rejected Christ and blasphemed God. Yet God graciously convicted him of sin and brought him to repentance and faith (Acts 9).
I don’t think we can figure out exactly what the unforgivable sin is. Jesus didn’t spell it out in detail. But it should make us very sober that a person could arrive at such a place.
And if you are sober about this you’ll be asking, "Have I committed the unforgiveable sin?" The unbelieving Pharisees wouldn’t have even asked this question because they were so confident of their righteousness. So if you are asking the question, it’s a good sign that God has given you a humble and repentant heart. God promises that "Everyone who calls on the name of the Lord will be saved" (Rom 10:13). God delights in forgiving all repentant sinners (Luke 15).
But we should never take his grace for granted. We can’t play around with sin thinking we can always repent tomorrow. The day may come when you have become so hardened and blinded by your sin that you no longer want to repent, which is a horrible place to be (Heb 12:17).