Langevin, in his 11th term, has represented the 2nd district for his entire House career. He won by a 17% margin in 2020. While redistricting isn't yet complete, a proposed map put forth last week by the Rhode Island Special Commission on Reapportionment would change very little.
As WPRI reports, "While Republicans haven’t won a U.S. House race in Rhode Island since the 1990s, the 2nd District is friendlier to the GOP than the 1st District — held by David Cicilline — giving the party hope of being competitive if a strong Republican candidate emerges."
McNerney made his announcement just minutes after Langevin. He is in his 8th term, having represented the 9th district since redistricting after the 2010 Census. While still favoring Democrats, the district became slightly more competitive in recent redistricting. Under the current borders, Joe Biden beat Donald Trump by 18%; that margin drops to about 13%.
Today I am announcing that I will not seek reelection in California’s newly created 9th Congressional District.
After McNerney's announcement, Rep. Josh Harder (CA-10), said he would move to run in the new 9th district. This is a bit more favorable Democratic territory than the new 13th district, where he had initially planned to run. Now without an incumbent, the 13th may be more in play; the current consensus (before Harder's move) is leans Democratic.