In terms of colors, your aim should be to make the CTA stand out. If the background color of your CTA is in low contrast with the button text, it will be less visible. Increase visibility by choosing high-contrast colors. Try to stick to a narrow palette of up to 4 main colors on a webpage and make sure your CTA stands out from the rest of the page with a unique color. A/B test the button color to determine the color that converts the best.