Conclusion

Nowadays, digital transformation is an unavoidable choice for any company, regardless of size or sector. Leaders cope with new tools on a daily basis and they make decisions according to the data they have access to. Therefore, we highly encourage future research to shed more light on the effect of digital transformation on leadership, both at organizational and individual level. If the debate about the relationship between human beings and machine is not a recent one, not to management literature, nor social sciences in general, the relationship between digital transformation and leadership requires updated lenses. This systematic review offers a structured framework of a promising field, and we hope it will help future research generate coherent efforts to garner novel and relevant knowledge in this research topic.

The purpose of this review was 3-fold. First, we discussed how leadership in the digital era has been conceptualized, reviewing the theoretical perspectives that have been used in prior research. Our review did not reveal a strong unifying theory of the relationship between leadership and digital transformation, thus calling for more attention to theoretical contributions.

Second, we mapped the academic debate on the relationship between digital transformation and leadership, organizing and structuring the main emerging themes at macro and micro level of analysis. We observed that both contributions with micro and macro approaches underscore that information technology and strategic management need greater alignment. Digital transformation is successful in the long term when the overall organizational objectives match the need to adopt new digital tools or instruments. In a similar vein, individuals embrace technological advancement only when they perceive it is relevant to their tasks. It is an important responsibility of the leader, particularly of C-level leaders, to steer this strategic alignment and the proliferation of a digital culture.

In a networked economy, the digital transformation has led organizations to open their boundaries, and connect with other industries, stakeholders, and customers, to generate innovation. From a micro perspective, this openness is also required by leaders who need to invest in networking. This means to be "out there", present in the network, and willing to communicate with different types of stakeholders, through digital tools and social media. Especially for leaders, digital tools are no longer a distant container of everyday life; rather, they are instruments in which everyday life emerges.

Although the introduction of digital tools influenced organizational boundaries and leadership boundaries, for instance favoring the development of concepts such as shared leadership, studies show that trust among members and employees is still achieved and maintained through leaders' intervention. Cascio and Montealegre, reminds us that inspirational leaders will remain pivotal in making the right decisions, as "humans will continue to enjoy a strong comparative advantage over machines". However, the growing development and use of AI-based technology to make decisions, calls for a closer understanding of what leadership will mean in the future. Growing ethical concerns related to the application of AI in managerial activities as well as to the appropriation of technology and data are becoming an urgent topic to address.

To overcome the challenges derived from the digital transformation, leaders are required to develop a combination of digital and human skills, mainly related to the ability to communicate effectively in a digitalized context, create cohesion between geographically distant followers, foster initiative and change attitudes, and deal with complex and fast problem solving.

Third, we highlighted the current gaps and open questions in the literature, and laid out a future research agenda that targets opportunities for the empirical and theoretical advancement of knowledge.

While our review is timely and includes the most recent contributions, some limitations should be considered and overcome in future studies. First, since our concern was to map prior research, we have not provided detailed propositions to the suggested categories, a void that should be addressed by future studies. The second concern regards the sample. We drew from the Scopus database only. Albeit we checked other databases to avoid potential bias, we may have missed some relevant articles contained elsewhere. Third, despite the rigorous procedure of our systematic review, a limitation is ascribed to the inclusion of only peer-reviewed articles and conference proceedings. A future review should also include industry research reports, professional outlets publishing research-based findings, and other non-peer reviewed manuscripts to better clarify how the multidimensional phenomenon of digitalization is affecting organizations and leadership. Finally, we excluded, as per our boundary conditions, articles that considered organizations as leaders in the digital transformation, and studies that discuss digital platforms. Future studies should adopt a broader overview of the macro-organizational and strategic effects in order to understand how digital transformation is implemented across different organizations, communities and teams.