ThThis question used to be asked this way, “what about people in deepest, darkest Africa who never hear about Jesus?” But these days it is more likely that it is people in deepest darkest Europe and Australia who have never heard about Jesus. In fact, the average Christian is more likely to be African or Asian than from European backgrounds.
So what does happen to people who have never heard? Romans 1:20 tells us that God’s invisible qualities such as his wisdom and power are evident from creation. The writer of Psalm 19 says that the heavens declare the glory of God. In other words, even if no one has ever told you about the death of Jesus on the cross for your sins to bring you to God, you still know that God exists, and that he is wise and powerful, from the creation around us. Romans 1:20 says that for this reason men are without excuse before God. In other words, you cannot say that you didn’t know because if you have eyes that work, you’ve got enough to go on.
The very interesting thing is what Romans 1 says that humans do with that knowledge: they exchange it for futile thinking, foolishness and lies and instead worship created things, rather than the creator God. And the evil which flows out from humanity is an extension of worshipping the wrong things. For these things people will experience just judgment (Romans 1 says that the evil which exists in society is in some way a part of God working that stuff out).
This is the reason why we need people to teach us about Jesus from his word. But there is still hope for those who don’t get given a Bible in their native tongue or otherwise hear the gospel. That hope rests with the mercy of God if people humbly ask him to reveal himself to them. In Matthew 6 Jesus tells people to ask, seek and knock, and promises that those who ask with humility will be answered by God. He may do that in miraculous ways for those people who wouldn’t otherwise have access to the Bible or other Christians. But usually he reveals himself through his word in the Bible as Christians share it with their friends and families.