The future will be negotiated on a regulated and opern market and probably CME volumes will be really bigger than Exchange volumes. Also 10 times the exchamge volumes. So, in the market, people will psicologically be influenced more by future than by real BTC. This is normal for every real asset that has a negotiated future. Wen you open television and they talk about oil price, they don't say "oil at the saudi oil camp is...." but they say "future's prices are...". So with CME futures some big market shocks can be trasmitted to Bitcoin.
Then, banks and great investors will easily be able to short bitcoin shorting the future. This will greatly affect the BTC market, because on CME will be moved really huge volumes. Not bilions or milions, trilions of daily volume. This is the enormous liquidity that is moved with CME, and this is what will enter in BTC future market.
CME futures will be dominated by trading volumes of great investors and bank, also with hyper-tecnologic methods like High Frequency Trading (you can find some valuable info at https://www.investopedia.com/terms/h/high-frequency-trading.asp), as every traditional financiary market. We will see great games, includind probably flash crashes on future.
So, pay a lot of attention. Surprises are really, really possible.