Maybe not, but I think that any attack add definitely has the possibility to potentially hurt his campaign and ability to win the election for the GOP candidate early next year. Hopefully people will be more upset with Ted Cruz more than Marco Rubio since Cruz is the one playing dirty!
Immigration is a key issue for GOP voters in this election and they won't favor Rubio's relaxed stance on immigration reform. As seen with Trump's campaign, GOP voters rally to candidates who promise a tougher stance on the issue of immigration. Given these factors, Cruz's attack ads against Rubio's stance on the issue may hurt Rubio's nomination chances.
If anything, I think that this will actually help Rubio. I think there are a lot of undecided and independent voters, as well as some Democrat voters who do not like their Democratic options this election cycle. These people are more likely to favor Rubio for his stance on immigration, and these ads will only help him.
No, Ted Cruz's latest TV ad attacking Marco Rubio's immigration stance will not hurt Rubio's chances of winning the GOP Nomination for President. It will likely have some small affect, but overall, it will be one small ripple in a very long campaign. Rubio and Cruz will likely continue to debate immigration because it is one of the few factors that separate them.