diff --git a/optimization/optimizers/cma_es/cma_es.h b/optimization/optimizers/cma_es/cma_es.h
index 7cdfa004ab4a144415a2b7b1181fc48111f06275..4994c35477c81c4204087e33ac7a995eb3c14b33 100644
--- a/optimization/optimizers/cma_es/cma_es.h
+++ b/optimization/optimizers/cma_es/cma_es.h
@@ -35,6 +35,7 @@ public:
     inline Eigen::Map<const Eigen::MatrixXd> point();
     Scalar value() { return cmaes_Get(&cma_es_, "fbestever"); }
 
+    // TODO: Support passing initial point by rvalue reference.
     template <typename Objective>
     Eigen::Map<const Eigen::MatrixXd> optimize(
         Objective& objective,
diff --git a/optimization/optimizers/gradient_descent/gradient_descent.h b/optimization/optimizers/gradient_descent/gradient_descent.h
index e8a7bf680c24a7533b6b509a330717b4291f1598..77968c353c04f49fb3766e784ea5dab513ef1ca6 100644
--- a/optimization/optimizers/gradient_descent/gradient_descent.h
+++ b/optimization/optimizers/gradient_descent/gradient_descent.h
@@ -25,6 +25,7 @@ public:
     VectorNs<N> const& gradient() const { return gradient_; }
     Scalar value() const { return value_; }
 
+    // TODO: Support passing initial point by rvalue reference.
     template <typename Objective>
     VectorNs<N> const& optimize(Objective& objective, VectorNs<N> const& initial_point);