The F-35 has made its official combat debut over Syria. Israel has confirmed that at least 2 F-35I Adir low observable multirole fighters were used in an operation to strike targets in Syria. It is unclear what particular operation it was used in or if the aircraft conducted Strike, ISR or Escort. 

The F-35I is ideal for the challenges faced in Syria due to Syria’s integrated air defense network. Several mobile early warning radar sites connect to advanced Pantsir,BUK and Tungkusk short/medium range SAMs and older long range SA-5 and SA-2 systems. The volume of surface to air missiles in such a small area make Pro Assad airspace heavily contested and dangerous for non stealth F-15 and F-16s.

In addition to the Syrian SAM systems Irans Revolutionary Guard Corp Aerospace force operates advanced TOR short range missile systems and the Russian Aerospace operates advanced S300 and S400 systems.

The F-35I Adir able to circumvent these systems by not allowing them to achieve radar lock. Because of this F-35s were likely used for SEAD and target designation for F-16I and F-15Is using Popeye long range stand off missiles.
The US Marine Corps F-35B will likely see combat against ISIL in its upcoming fall deployment.