  Caccetta-H\"{a}ggkvist conjecture is a longstanding open problem on degree
conditions that force an oriented graph to contain a directed cycle of a
bounded length. Motivated by this conjecture, Kelly, K\"uhn, and Osthus
initiated a study of degree conditions forcing the containment of a directed
cycle of a given length. In particular, they found the optimal minimum
semidegree, that is, the smaller of the minimum indegree and the minimum
outdegree, which forces a large oriented graph to contain a directed cycle of a
given length not divisible by 3, and conjectured the optimal minimum semidegree
for all the other cycles except the directed triangle.
  In this paper, we establish the best possible minimum semidegree that forces
a large oriented graph to contain a directed cycle of a given length divisible
by 3 yet not equal to 3, hence fully resolve the conjecture by Kelly, K\"{u}hn,
and Osthus. We also find an asymptotically optimal semidegree threshold of any
cycle with a given orientation of its edges with the sole exception of a
directed triangle.
