Review for NeurIPS paper: Pipeline PSRO: A Scalable Approach for Finding Approximate Nash Equilibria in Large Games

Weaknesses: The paper is missing a comparison with the most relevant previous work, namely XFP [1] Heinrich, Johannes, and David Silver. Both of these works are mentioned in the Background and Related Work, but: 1) XFP is just mentioned but never compared to in experiments 2)DeepCFR is just discarded with "However, Deep CFR uses external sampling, which may be impractical for games with a large branching factor such as Stratego and Barrage Stratego." Furthermore, there are newer variants based on this work, and it is not limited to a particular form of sampling. The paper only really compares to other variants from the PSRO family Furthermore, the theory and algorithms (the way described in the text) deal only with matrix games, while the experiments are on extensive form games. If the goal is to run on top of the exponentially large matrix game, this should be discussed.