user109336: Have you ever witnessed any front-running case in Bitcoin?
All front running cases are related to Ethereum smart contracts, auto market makers and uniswap.
Thank you

user7144: Front-running (in the case you're referring to) is a concept related to on-chain trading, where miners order transactions to affect the exchange rates of smart contracts. Since bitcoin does not currently support smart contracts, ordering of transactions cannot affect the miner, as there is nothing to front-run.

user-1: 
Have you ever witnessed any front-running case in Bitcoin?

I have not witnessed and consider there are less incentives in Bitcoin for front running, MEV etc. Although there might have been few cases in past and there are other use cases where mining involvement can extract value; e.g. miners could delay Lightning disputes

All front running cases are related to Ethereum smart contracts, auto market makers and uniswap

Front running and MEV was mentioned in https://www.paradigm.xyz/2020/08/ethereum-is-a-dark-forest/ and I will quote 2 paragraphs from it:
In the Ethereum mempool, these apex predators take the form of “arbitrage bots.” Arbitrage bots monitor pending transactions and attempt to exploit profitable opportunities created by them. No white hat knows more about these bots than Phil Daian, the smart contract researcher who, along with his colleagues, wrote the Flash Boys 2.0 paper and coined the term “miner extractable value” (MEV).
Phil once told me about a cosmic horror that he called a “generalized frontrunner.” Arbitrage bots typically look for specific types of transactions in the mempool (such a DEX trade or an oracle update) and try to frontrun them according to a predetermined algorithm. Generalized frontrunners look for any transaction that they could profitably frontrun by copying it and replacing addresses with their own. They can even execute the transaction and copy profitable internal transactions generated by its execution trace.
Difference between Bitcoin and Ethereum that increases the probability of front running in Ethereum:





Bitcoin
Ethereum




DEX
Layer 2   (Exception: Bisq although it works differently)
Mostly On-chain


Oracles
DLC not used by many projects yet
Used and exploited regularly


Unconfirmed transactions
Mempool
TxPool


Block size
4,000,000 weight units (WU)
15,000,000 gas units


Block Interval
Average: 10 minutes
Few seconds


Failed transactions
Zero
Thousands per day




Maybe lot of other things that are different and incentivize front running.

109336: <p>Have you ever witnessed any front-running case in Bitcoin?
All front running cases are related to Ethereum smart contracts, auto market makers and uniswap.</p>
<p>Thank you</p>
 7144: <p>Front-running (in the case you're referring to) is a concept related to on-chain trading, where miners order transactions to affect the exchange rates of smart contracts. Since bitcoin does not currently support smart contracts, ordering of transactions cannot affect the miner, as there is nothing to front-run.</p>
 -1: <blockquote>
<p>Have you ever witnessed any front-running case in Bitcoin?</p>
</blockquote>
<p>I have not witnessed and consider there are less incentives in Bitcoin for front running, MEV etc. Although there might have been few cases in past and there are other use cases where mining involvement can extract value; e.g. miners could delay Lightning disputes</p>
<blockquote>
<p>All front running cases are related to Ethereum smart contracts, auto market makers and uniswap</p>
</blockquote>
<p>Front running and MEV was mentioned in <a href="https://www.paradigm.xyz/2020/08/ethereum-is-a-dark-forest/" rel="nofollow noreferrer">https://www.paradigm.xyz/2020/08/ethereum-is-a-dark-forest/</a> and I will quote 2 paragraphs from it:</p>
<p><em>In the Ethereum mempool, these apex predators take the form of “arbitrage bots.” <strong>Arbitrage bots</strong> monitor pending transactions and attempt to exploit profitable opportunities created by them. No white hat knows more about these bots than Phil Daian, the smart contract researcher who, along with his colleagues, wrote the Flash Boys 2.0 paper and coined the term “<strong>miner extractable value</strong>” (MEV).</em></p>
<p><em>Phil once told me about a cosmic horror that he called a “generalized frontrunner.” Arbitrage bots typically look for <strong>specific types of transactions in the mempool</strong> (<strong>such a DEX trade or an oracle update</strong>) and try to <strong>frontrun</strong> them according to a predetermined algorithm. Generalized frontrunners look for <strong>any transaction that they could profitably frontrun by copying it and replacing addresses with their own</strong>. They can even execute the transaction and copy profitable internal transactions generated by its execution trace.</em></p>
<p>Difference between Bitcoin and Ethereum that increases the probability of front running in Ethereum:</p>
<div class="s-table-container">
<table class="s-table">
<thead>
<tr>
<th style="text-align: left;"></th>
<th style="text-align: center;">Bitcoin</th>
<th style="text-align: right;">Ethereum</th>
</tr>
</thead>
<tbody>
<tr>
<td style="text-align: left;">DEX</td>
<td style="text-align: center;">Layer 2   (Exception: Bisq although it works differently)</td>
<td style="text-align: right;">Mostly On-chain</td>
</tr>
<tr>
<td style="text-align: left;">Oracles</td>
<td style="text-align: center;">DLC not used by many projects yet</td>
<td style="text-align: right;">Used and <a href="https://samczsun.com/so-you-want-to-use-a-price-oracle/" rel="nofollow noreferrer">exploited</a> regularly</td>
</tr>
<tr>
<td style="text-align: left;">Unconfirmed transactions</td>
<td style="text-align: center;"><a href="https://bitcoin.stackexchange.com/questions/96068/what-if-the-mempool-exceeds-300-mb">Mempool</a></td>
<td style="text-align: right;"><a href="https://ethereum.stackexchange.com/questions/3773/what-is-the-name-of-pool-which-keeps-transactions-in-memory-such-as-bitcoins-me">TxPool</a></td>
</tr>
<tr>
<td style="text-align: left;">Block size</td>
<td style="text-align: center;">4,000,000 <a href="https://bitcoin.stackexchange.com/questions/98810/whats-the-blocksize-limit-after-segwit-and-how-do-legacy-nodes-deal-with-segwit/">weight units</a> (WU)</td>
<td style="text-align: right;">15,000,000 <a href="https://etherscan.io/chart/gaslimit" rel="nofollow noreferrer">gas units</a></td>
</tr>
<tr>
<td style="text-align: left;">Block Interval</td>
<td style="text-align: center;">Average: 10 minutes</td>
<td style="text-align: right;">Few seconds</td>
</tr>
<tr>
<td style="text-align: left;">Failed transactions</td>
<td style="text-align: center;">Zero</td>
<td style="text-align: right;">Thousands per day</td>
</tr>
</tbody>
</table>
</div>
<p>Maybe lot of other things that are different and incentivize front running.</p>
