No trigger word needed. But here are some tips that you can use to make the style look more accurate:
PDXL:
In the Negative Prompt you can put "3d".
You can increase the strength of the lora.
You can also use "score_9, score_7_up" without "score_8_up" for better accuracy.
Illustrious:
In the Negative Prompt you can put "anime, 3d".
I recommend put 1.2 strength to the lora.
Also use "2d, shaded, official art, toon \(style\)" for better accuracy.