Abstract: For this special section on software systems, several research leaders in software systems, as guest editors for this special section, discuss important issues that will shape this field's future directions. The essays included in this roundtable article cover research opportunities and challenges for emerging software systems such as data processing programs (Xiangyu Zhang) and online services (Dongmei Zhang), with new directions of technologies such as unifications in software testing (Yves Le Traon), data-driven and evidence-based software engineering (Qing Wang), and dynamic analysis of multiple traces (Lu Zhang).——Tao Xie, Leading Editor of Special Section on Software System.