Hi @Pui
This will be a setting on the TV side. It's different for everybrand but see if you can go to the TV menu and select a picture option for that HDMI. Something like "movies" or "cinematic" or "vibrant". Change picture settings on your TV and that should help.
You can also try plugging the Chromecast into a different HDMI input on the TV. That also may change the picture setting that the TV.
