This review discusses the toxicities associated with cancer immunotherapies, including checkpoint inhibitors and chimeric antigen receptor (CAR) T cells. These therapies, which manipulate the immune system to target cancer cells, have transformed treatment for various malignancies but can cause unique toxicities. These toxicities, such as cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), require specific management and are often managed with steroids or immunomodulating agents. The review focuses on the pathophysiology, diagnosis, and management of these toxicities. Checkpoint inhibitors, such as those targeting PD-1 and CTLA-4, can cause immune-related adverse events (irAEs), including inflammatory side effects like colitis, hepatitis, and hypophysitis. These toxicities are often dose-dependent and can be severe, requiring immediate intervention. The incidence of irAEs varies by agent and treatment regimen, with higher rates observed with combination therapies. Management of irAEs includes corticosteroids, biologic therapies, and other immunosuppressive agents. Dermatologic toxicity is the most common irAE, with symptoms ranging from mild rashes to severe conditions like Stevens-Johnson syndrome. Gastrointestinal toxicity, including diarrhea and colitis, is also common, with treatment involving corticosteroids and, in some cases, biologics like infliximab or vedolizumab. Hepatotoxicity, such as hepatitis, can occur with checkpoint inhibitors and requires monitoring and management with corticosteroids or other immunosuppressive agents. Endocrinopathies, including hypothyroidism, hyperthyroidism, and hypophysitis, are also associated with ICI therapy. These conditions often require lifelong hormone replacement and close monitoring. Thyroid toxicity, with hypothyroidism being more common, can lead to severe complications if not managed properly. Pneumonitis is a significant pulmonary toxicity associated with ICI therapy, often requiring immunosuppressive treatment. Rheumatologic toxicities, such as arthritis and myositis, can also occur, necessitating collaboration with rheumatology. Neurologic toxicities, including encephalitis and myasthenia gravis, are rare but can be severe, requiring prompt intervention. Renal toxicity, including acute kidney injury, is rare but can occur with ICI therapy. The management of these toxicities requires close monitoring, timely intervention, and multidisciplinary collaboration to ensure patient safety and optimal outcomes.This review discusses the toxicities associated with cancer immunotherapies, including checkpoint inhibitors and chimeric antigen receptor (CAR) T cells. These therapies, which manipulate the immune system to target cancer cells, have transformed treatment for various malignancies but can cause unique toxicities. These toxicities, such as cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), require specific management and are often managed with steroids or immunomodulating agents. The review focuses on the pathophysiology, diagnosis, and management of these toxicities. Checkpoint inhibitors, such as those targeting PD-1 and CTLA-4, can cause immune-related adverse events (irAEs), including inflammatory side effects like colitis, hepatitis, and hypophysitis. These toxicities are often dose-dependent and can be severe, requiring immediate intervention. The incidence of irAEs varies by agent and treatment regimen, with higher rates observed with combination therapies. Management of irAEs includes corticosteroids, biologic therapies, and other immunosuppressive agents. Dermatologic toxicity is the most common irAE, with symptoms ranging from mild rashes to severe conditions like Stevens-Johnson syndrome. Gastrointestinal toxicity, including diarrhea and colitis, is also common, with treatment involving corticosteroids and, in some cases, biologics like infliximab or vedolizumab. Hepatotoxicity, such as hepatitis, can occur with checkpoint inhibitors and requires monitoring and management with corticosteroids or other immunosuppressive agents. Endocrinopathies, including hypothyroidism, hyperthyroidism, and hypophysitis, are also associated with ICI therapy. These conditions often require lifelong hormone replacement and close monitoring. Thyroid toxicity, with hypothyroidism being more common, can lead to severe complications if not managed properly. Pneumonitis is a significant pulmonary toxicity associated with ICI therapy, often requiring immunosuppressive treatment. Rheumatologic toxicities, such as arthritis and myositis, can also occur, necessitating collaboration with rheumatology. Neurologic toxicities, including encephalitis and myasthenia gravis, are rare but can be severe, requiring prompt intervention. Renal toxicity, including acute kidney injury, is rare but can occur with ICI therapy. The management of these toxicities requires close monitoring, timely intervention, and multidisciplinary collaboration to ensure patient safety and optimal outcomes.