In a medium bowl, combine mayonnaise and sour cream.
Add lime juice and mix until smooth.
Sprinkle in chili powder, garlic powder, and cumin.
Stir the mixture until well combined.
Add chopped cilantro and mix gently.
Season with salt and pepper to taste.
For extra heat, fold in finely chopped jalapeño (optional).
Taste and adjust seasoning if necessary.
Cover the bowl with plastic wrap.
Refrigerate for at least 30 minutes to let the flavors meld.