Bring a large pot of salted water to a boil. Add the penne pasta and cook until al dente, about 10-12 minutes. Drain and set aside.

In a large skillet, heat olive oil over medium-high heat. Season chicken with Cajun seasoning, and sauté for 4-5 minutes on each side until cooked through. Transfer to a plate and keep warm.

In the same skillet, add shrimp and cook for 2-3 minutes until pink and opaque. Remove and set aside with the chicken.

Add more olive oil if needed, then sauté andouille sausage for 2 minutes. Add bell peppers, red onion, and garlic, cooking until vegetables are tender, about 4 minutes.

Pour in heavy cream and stir to combine. Simmer for 2-3 minutes until slightly thickened. Stir in Parmesan cheese until melted, and adjust seasoning.

Return chicken and shrimp to the skillet, add cooked pasta, and toss gently to combine. Heat for an additional 1-2 minutes.

Sprinkle with chopped parsley and serve warm.