Immunotherapy with checkpoint inhibitors is an effective strategy for several cancers. In some patients long-term remissions are seen. However, enhancement of the immune response can be accompanied by immune-related adverse events (irAEs). These patients often present with nonspecific symptoms. The most common irAEs are dermatitis, colitis, pneumonitis, hepatitis and endocrinopathies. IrAEs can occur in every organ, even simultaneously. Furthermore, irAEs can occur weeks or months after discontinuation of checkpoint inhibitors. Most irAEs can be well managed, but life-threatening situations do occur. General management involves supportive care, glucocorticoids and sometimes immunomodulatory drugs, such as infliximab. Early diagnosis and adequate team management can improve the course of irAEs without compromising the cancer treatment. Here, we present two cases: a melanoma patient with an ipilimumab-induced colitis and a lung cancer patient with pneumonitis after anti-PD-1.We then summarise the most common toxicities of checkpoint inhibitors, emphasising the need to familiarise the practitioner with irAEs of approved and emerging immunotherapies.