Cook the pasta according to the package directions; drain, reserving 1/2 cup of the pasta cooking water.
While the pasta is cooking, combine the Pesto and Marinara sauce in a large pot, bring to a simmer, cover and keep warm.
Add the cooked pasta to the sauce and toss, adding the pasta water a little at a time to loosen the sauce if necessary. Season with salt and pepper to taste, divide among bowls and garnish with cheese and basil.