The advent of immunotherapy and specifically of immune checkpoint inhibitors (ICIs) for the treatment of solid tumors has deeply transformed therapeutic algorithms in medical oncology. Approximately one third of patients treated with ICIs may develop immune-related adverse events, being the gastrointestinal tract often affected with different grades of mucosal inflammation. Checkpoint inhibitors colitis (CIC) presents with watery or bloody diarrhoea and in case of severe activity requires ICIs discontinuation. The pathogenesis of CIC is multifactorial and still partially unknow: anti-tumor activity that collaterally effects the colonic tissue and the upregulation of specific systemic inflammatory pathways (i.e., CD8+ cytotoxic and CD4+ T lymphocytes) are mainly involved. Many open issues remain on treatment timing and options, and biological treatment, above all with anti-TNF alpha, can be offered to these patients aiming to rapidly resume the oncological therapies. This review aims to summarize the pathogenetic mechanisms underlying CIC and to discuss evidenced-based management including the role of biological therapy.