The earliest cybernetic systems were prostheses for disabled or impaired individuals, such as hearing-aid implants and pacemakers. Early in the 21st century, the first systems that linked the user's nervous system with electronics were available, allowing paralyzed individuals to control computers and setting the stage for bionic eyes and advanced limb replacements. At the same time, non-medical applications were also being developed, such as 'hands-free' control interfaces for space suits, infantry equipment, and vehicles.
Bionic libms and organs were common in the 21st century, but are now more rare, often replaced by tissue-engineered transplants easier to grow than bionics were to manufacture. Bionic libms or organs aimed at enhancing a person's abilities are even rarer. It's cheaper and easier just to use gadgets, such as a pair of infrared goggles or a powered suit, and far easier to fix things external to the body if and when they break down. Also, while bionics do allow covert operators to use hidden 'surprise' devices, any serious opponent (such as a spaceport customs check) will detect the bionics with sensors. If subtlety is called for, biological modifications or tinier implants are used instead.