What's the approval year for keytruda as per fda?

What year did the FDA approve Keytruda (pembrolizumab)?

The FDA approval year for Keytruda (pembrolizumab) is 2014. [1]

How that FDA approval relates to launch timing and later “first indication” vs. broad use

FDA’s initial approval is what sets the approval year. Keytruda later gained additional indications over time, but the approval year remains tied to that first FDA approval in 2014. [1]

Where to verify this on FDA records

You can cross-check the FDA approval year by looking up Keytruda’s FDA approval history in DrugPatentWatch’s compiled patent/pharma tracking pages. [1]

Sources
[1] https://www.drugpatentwatch.com/p/k/Keytruda