Massive multiple-input multiple-output (MIMO) is a dominant technology that, combined with advanced techniques and architectures, is set to play an integral role in the next-generation wireless systems. This cutting-edge technology has proved its adaptability and scalability in 5G networks by producing significant results. Recent years have seen a remarkable succession of evolutionary breakthroughs leading to revolutionary trends projected to transform future 6G wireless systems drastically. Terahertz (THz) communication, artificial intelligence (AI), cell-free structures, intelligent omni-surfaces/intelligent reflecting surfaces (IOS/IRS), and other technologies will further improve the performance capabilities of large MIMO. Furthermore, the range of diversified applications based on massive MIMO's foundation include vehicle communications, wireless localization and sensing, inter-planetary communications remote sensing, etc., and these are continuously expanding.