Does Premiere Pro have Color Masks?

There are a couple of ways to do this.

With 3 layers

1. Stack 3 copies of the same clip on V1 to V3.
2. Create the color mask on V3. Open the Lumetri Color panel, go to HSL Secondary, and use the color pickers to select your colors. Adjust the H, S, and L sliders to set the color range and softness.
3. Under the H/S/L sliders, click the dropdown and choose White/Black. This turns your mask into a luma matte.
4. On V2, add the Track Matte Key effect. Set Matte to Video 3 and Composite Using to Matte Luma.

This masks everything except the color selection you made on V3. Add your effects below the Track Matte Key effect, and they will affect only your color selection.

Note: The Track Matte Key effect will not work correctly if the footage is scaled in the timeline.

With 2 layers

1. Stack 2 copies of the same clip on V1 and V2.
2. Create the color mask on V2. Open the Lumetri Color panel, go to HSL Secondary, and use the color pickers to select your colors. Adjust the H, S, and L sliders to set the color range and softness.
3. Under the H/S/L sliders, click the dropdown and choose Color/Black. This makes everything in V2 black except for the color selection.
4. Add the Ultra Key effect to V2 to mask the black. Ultra Key selects black by default. You may need to further refine the softening with the Ultra Key controls.

Add your effects below the Ultra Key effect, and they will affect only your color selection.

Note: Applying Ultra Key can cost you some of the edge detail from your HSL Secondary mask, and you will have two separate sets of controls for refining edges and softening, one in HSL Secondary and one in Ultra Key.