For most of the major brands, they will have an official website. They will have the most up-to-date ETA as the manufacturer.
You should also be able to see their latest releases via their social media such as Facebook/Instagram/Twitter. Some brands will have a collectors group.
The quickest way is to google this product and you should be directed to the offcial product page on their website.
Examples are:
Sideshow - https://www.sideshow.com/
Prime 1 Studio - www.prime1studio.com
Hot Toys - https://www.facebook.com/hottoys
Blitzway - https://blitzway.com/
Infinity Studio - https://www.instagram.com/infinitystudiocn/
Queen Studios - https://queenstudios.shop/