In Cyberknights Flashpoint, your team will have three reasons to go under the knife and receive treatments or surgeries from medical Contacts: Treating Injuries, Curing Wounds, and Enhancing your team with Cybernetics.
For Treating Injuries and Wounds see Injury, Bleeding, and Recovery.
Surgery can selected from the Safehouse to treat Injuries (downtimes from participating in further missions or Legwork). Treating such injury will speed up the recovery for that mercenary, but will occupy a medical contact's time and will cost a sum of money.
Once injuries have been dealt with, the persistent wounds can be treated at an additional cost in both time and money. This activity also occupies your contact's attention preventing other medical services while they focus.
Installing cybernetics will require significant money, time, and medical attention as well, but in return, each piece of cybernetics offers powerful benefits. Most cybernetics also have at least a small additional downside, such as reduced stress resistance. Some cybernetics are required to unlock specialization sub-branches on the Training tree(s), while others are needed to unlock an entire Class like the Vanguard or Hacker.
Cybernetics have a category they're associated with such as "Lungs". You can only have one piece of cybernetics per category. You can have a maximum of six cybernetic systems per mercenary. The Cyber Knight's quantum computer is required to fill one of his/her slots, but can be upgraded with a more powerful version in the future offering different/additional bonuses.
Here is a list of cyberware types.