NFTs that were minted on GameStop NFT are tradable on the marketplace.
That means if you own an NFT that originated outside of GameStop NFT, it will not currently be tradable.
As we grow, however, we will be supporting collections that were minted outside of GameStop NFT on the Ethereum environments that the marketplace supports.
For a list of supported environments, see this article: List of blockchains, layers, and networks that are compatible with GameStop NFT