Bring a large pot of salted water to boil. Add the linguine or fettuccine and cook according to package instructions until al dente. Reserve ½ cup of pasta water, then drain and set aside.
Heat 1 tablespoon of olive oil in a large skillet over medium-high heat. Add the sliced turkey sausage and cook until browned and slightly crispy, about 4-5 minutes. Remove the sausage from the skillet and set aside. In the same skillet, add the remaining tablespoon of olive oil and toss in the shrimp. Season them lightly with salt and pepper and cook for 1-2 minutes per side until pink and opaque. Remove the shrimp and set aside with the sausage.
Reduce the heat to medium. Add the diced onion and chopped bell pepper to the skillet. Sauté until softened and fragrant, about 3-4 minutes. Stir in the minced garlic and cook for an additional 30 seconds until aromatic.
Pour in the chicken broth and heavy cream, stirring to combine. Sprinkle in the Cajun seasoning, salt, and pepper, then bring the mixture to a gentle simmer. Let it cook, stirring occasionally, until the sauce thickens slightly, about 4-5 minutes.
Return the cooked sausage and shrimp to the sauce. Add the drained pasta and toss everything together. If the sauce feels too thick, add reserved pasta water a little at a time until you reach your desired consistency.
Remove from heat and sprinkle with freshly chopped parsley. Serve immediately for the best flavor and texture.