  In this paper, we solve the abundance conjecture for minimal projective klt
varieties $X$ satisfying Miyaoka's equality $3c_2(X) = c_{1}(X)^{2}$.
Specifically, we prove that the canonical divisor $K_{X}$ is semi-ample and the
Kodaira dimension $\kappa(K_{X})$ is either $0$, $1$, or $2$. Moreover,
according to the Kodaira dimension, we reveal the structure of the Iitaka
fibration of $X$ up to quasi-\'etale covers. Additionally, we show similar
results for projective klt varieties with nef anti-canonical divisor.
