The COVID-19 pandemic has affected all medical fields and brought up a lot of serious problems. The features of the COVID-19 infection in patients with cancer are important to understand. According to many articles, patients with cancer are more vulnerable to COVID-19 infection. Patients undergoing anticancer treatment have 1-4% morbidity rate. Patients with hematological diseases and lung cancer are at higher risk of SARS-CoV-2 infection and also have more severe symptoms and complications. In this article we discuss the effect of the tumors on the immune system and comprehend the pathogenesis of the coronavirus disease according to its impact on the immunity. Moreover, in the review we analyze available data about the influence of the different types of cancer therapy (chemotherapy, target therapy, radiotherapy and immunotherapy) on the severity of the COVID-19 infection. Evidence on the effect of chemotherapy on severity and mortality from COVID-19 is contradictory. Whereas there are some authors concluding that chemotherapy treatment is not affecting the severity of COVID-19 disease, there are also some works where the connection between these facts was established. At the same time target therapy, radio-and immunotherapy most likely do not worsen the SARS-CoV-2 infection and are not associated with the development of complications. But it’s important to say that the amount of data available for today is insufficient to make a unambiguous conclusion.