Quantum Chromodynamics (QCD) matter at finite temperature and density is a subject that has witnessed very impressive theoretical developments in the recent years. In this review, I will discuss some new insights on the microscopic degrees of freedom of the QCD medium near the chiral crossover transition coming from lattice QCD. Latest high precision lattice data on the fluctuations and correlations between conserved charges like the baryon number, strangeness can help us to understand and distinguish between different models of interacting hadrons. Furthermore, the latest constraints on the location of the critical end-point and the curvature of the critical line will be discussed. In the later part of this review, I will discuss about the insights on the thermal nature of the medium created in heavy-ion collision experiments that have come from the theoretical analysis of the particle yields, and to what extent the lattice data on correlations and fluctuations of conserved charges can give us any information about the fireball at freeze out.

中文翻译：

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QCD物质在有限温度和密度下的最新理论进展

有限温度和密度下的量子色动力学 (QCD) 物质是近年来取得了令人印象深刻的理论发展的学科。在这篇评论中，我将讨论一些关于 QCD 介质在来自晶格 QCD 的手性交叉跃迁附近的微观自由度的一些新见解。关于守恒电荷（如重子数、奇异性）之间波动和相关性的最新高精度晶格数据可以帮助我们理解和区分不同的相互作用强子模型。此外，还将讨论对临界端点位置和临界线曲率的最新约束。在这篇评论的后半部分，