It's just a stupid question and Jesus was putting him down in an easy way.

Christians should have their eyes on God and if the tax man wants caesers coins you should give them to him.

2/10 bait.

He obviously wouldn't be beheaded for this. And he spoke because it must be spoken, for Cesare owned those lands, and levied tax. The Scriptures report two instances where Jesus talked about taxes. See more explanatory in another excerpt :

"And they having come to Capernaum, those receiving the didrachmas came near to Peter and said, "Your teacher — does He not pay the didrachmas ?" He says, "Yes." And when he came into the house, Yeshua anticipated him, saying, "What do you think, Simon ? The kings of the earth — from whom do they receive custom or poll-tax ? From their sons or from the strangers ?" Peter says to Him, "From the strangers." Yeshua said to him, "Then the sons are free ; but that we may not cause them to stumble, having gone to the sea, cast a hook, and the fish that has come up first take up, and having opened its mouth, you will find a stater, that having taken, give to them for Me and you."" Matthew 17:23-27

And what did he mean in the last verse ? That for Gentiles not to be offended, and possibly for you not to get in trouble, it is better to pay tax.

Now, detailed explanation about "Caesar to Caesar...".

John Gill's Exposition of the Entire Bible :

https://www.biblestudytools.com/commentaries/gills-exposition-of-the-bible/matthew-22-21.html

"They say unto him, Caesar's,.... Either Augustus Caesar's; for there was a coin of that emperor's, as Dr. Hammond reports, from Occo, which had his image or picture on it, and in it these words written, Augustus Caesar, such a year, "after the taking of Judaea"; which if this was the coin, was a standing testimony of the subjection of the Jews to the Romans; and this being current with them, was an acknowledgment of it by them, and carried in it an argument of their obligation to pay tribute to them; or it might be Tiberius Caesar's, the then reigning emperor, in the nineteenth year of whose reign, Christ was crucified; and seeing he had reigned so long, it is reasonable to suppose, his money was very common, and most in use: we read in the Talmud {s}, of דינרא קיסראנה, "a Caesarean penny", or "Caesar's penny", the same sort with this: now this penny having Caesar's image and inscription on it, our Lord tacitly suggests, that they ought to pay tribute to him; since his money was allowed of as current among them, which was in effect owning him to be their king; and which perfectly agrees with a rule of their own, which runs thus {t}:

"A king whose "coin" is "current" in any country, the inhabitants of that country agree about him, and it is their joint opinion, שהוא אדוניהם והם לו עבדים "that he is their Lord, and they are his servants".''

This being the case now with the Jews, Christ's advice is,

render therefore unto Caesar the things which are Caesar's, and unto God, the things that are God's: give Caesar the tribute and custom, and fear, and honour, and obedience, which are due to him; which may be done without interfering with the honour of God, and prejudicing his interest and glory, when care is taken, that all the worship and obedience due to God are given to him: subjection to civil magistrates is not inconsistent with the reverence and fear of God; all are to have their dues rendered unto them, without entrenching upon one another. And the Jews themselves allow, that a king ought to have his dues, whether he be a king of Israel, or of the Gentiles:

"a publican, or tax gatherer, (they say {u},) that is appointed by the king, whether a king of Israel, or of the Gentiles, and takes what is fixed by the order of the government; it is forbidden to refuse payment of the tax to him, for דינא דמלכות דינא, "the right of a king is right".''

Just and equitable, and he ought to have his right.

{s} T. Bab. Avoda Zara, fol. 6. 2. {t} Maimon. Hilch. Gerala, c. 5. sect. 18. {u} Maimon. & Bartenora in Misn. Nedarim. c. 3. sect. 4. & Maimon. Hilch. Gezala, c. 5. sect. 11."

Caesar only wanted 1-3% depending on if they were in a war or not.