A real "Westworld" like on HBO is only 20 to 30 years away potentially

If you study the autonomy of robotic creations you can easily see that something like a real "Westworld" is possible very soon. However, for a lot of reasons you might see something like this in Saudi Arabia or in Japan or China before you would see this in the U.S. because we are more safety conscious. Countries more interested in the Technology over the safety of individual humans is likely where you are going to see a "Westworld" type of scenario play out first.

The biggest single obstacle I see at present would be batteries that are small enough and compact enough and rechargeable enough (that don't catch on fire ever). For example, most energetic animal like robots capable of running 45 miles per hour carrying a human soldier sort of like a goat or horse or mule or donkey have an engine sort of like a small motorcycle engine that creates power for the robot to run on. So, basically you have a gas generator  generating enough electricity for running something that can run 45 miles per hour on four legs carrying a human being now like a soldier through rough terrain with fairly extreme agility. However, I'm thinking the ride might jar your guts out to actually be doing something like this and most of the time you might want an off road motorcycle instead that has proper suspension or pegs to stand up on  to take the shocks so your innards don't get ruined. However, for carrying loads over ground not fit for a motorcycle this might work as long as the sound of the engine wouldn't get someone shot. So, maybe a 4 legged robot carrying munitions and carrying that stuff running alongside an off road military motorcycle we might see a lot in the future of the American military delta forces worldwide.