Since the start of the global spread of coronavirus disease (COVID-19) pandemic, cancer patients were identified as a specifically susceptible subgroup of the patient population. Several reports have shown that cancer patients have an increased risk of both contracting the infection and of experiencing a more severe disease course, with a rapidly evolving picture associated with higher mortality. The assumption of cancer patients as "COVID-19 vulnerable" has led, irretrievably, to profound changes in the decision making of oncological treatments. Potential justifications for such concerns encompass the cancer-dependent suppression of the immune response, as well as the influence of administration of systemic anticancer treatments, including chemotherapy and immunotherapy. Nevertheless, to date, it is not clear whether the use of immune checkpoint inhibitors (ICIs) in cancer patients is safe, given their modulating effects on the immune system, or that they may rather conceal detrimental consequences. Theoretically, on the one hand, ICIs may enhance the immunological control of viral infections through their immunostimulating mechanisms; on the other hand, they could contribute to the hyper-inflammatory phase of COVID-19, worsening its clinical outcomes. In this study, we report the foremost clinical observations on the safety of ICI administration in cancer patients affected by COVID-19.