In my view, that would greatly depend on what kind of futures they are going to introduce or have already introduced. There can be basically two kinds, I mean futures that are either cash settled or physically delivered. Obviously, futures contracts that require the actual underlying asset (Bitcoin) to be delivered will directly affect the market price of the underlying simply because this is equal to trading with real bitcoins. But as far as I know, bitcoin futures are only cash settled as of yet, so they shouldn't affect bitcoin and its price on their own.