Preheat oven to 350°F and line a 9x13-inch baking pan with parchment paper or grease well.
In a medium bowl, whisk together flour, cocoa powder, baking powder, and salt. Set aside.
In a large bowl, mix pumpkin puree, oil, 1 1/2 cups sugar, eggs, and vanilla until well combined and smooth.
Gradually fold the dry ingredients into the wet ingredients until just combined. Stir in chocolate chips.
Pour batter into prepared pan and spread evenly.
Beat cream cheese and 1/4 cup sugar together until smooth. Drop spoonfuls over the brownie batter.
Use a knife to swirl the cream cheese mixture into the brownie batter, creating a marbled effect.
Bake for 30-35 minutes, or until a toothpick inserted in the center comes out with just a few moist crumbs.
Let cool completely before cutting into 16 squares. Store in an airtight container for up to 4 days.