Perhaps no other case of conversion in the Bible receives as much attention as Cornelius, aside from Paul's own conversion. There are many things the Spirit wants us to learn by this example in this chapter and the next. We know in chapter 2 many prophecies were fulfilled upon the pouring out of the Holy Spirit. It was a promise fulfilled. Some say that what happens to Cornelius is a second outpouring but no such scriptural reference is made in this case. The Spirit was already poured out, available unto all who called on His name (Acts 2:21; 22:16). Here we see, about 10 years later, how the Gentiles were ushered into this promise which God intended all along.
YT: https://youtu.be/vNF7HgXT1oE