The famous Frankel conjecture says that a compact Kähler manifold with positive bisectional curvature must be biholomorphic to CPn. This conjecture was settled by Siu-Yau and Morri independently in the 80s. After the introduction of Ricci flow by R. Hamilton as a canonical way to deform metrics to the Einstein metric, it was natural to ask whether the Kähler-Ricci flow can deform any metric with positive bisectional curvature in CPn to the standard Fubini-Study metric. This is a long-standing problem in Kähler-Ricci flow and much progress was made; the problem was finally settled in 2000. What I am going to report on in this talk is an extension of the classical Frankel conjecture: Is a compact manifold with positive orthogonal bisectional curvature necessarily biholomorphic to CPn (the holomorphic sectional curvature may change sign)? Note that in complex dimension 1, every Riemannian surface has positive orthogonal bisectional curvature (since the condition is vacuous in dimension 1). I will try to answer this question in the seminar.