Immunotherapies and other novel agents currently being evaluated in combination with immunotherapies in patients with small-cell lung cancer include immune-checkpoint inhibitors (anti-programmed cell death protein 1 (PD-1), anti-programmed cell death 1 ligand 1 (PD-L1), anti-cytotoxic T lymphocyte protein 4 (CTL A-4), anti-L AG3 and anti-TIM3 antibodies), bispecific antibodies (such as those targeting CD3 plus DLL3 or PD-1 plus TIM3), engineered T cell therapies (such as anti-DLL3 chimeric antigen receptor (CAR) T cells), neoantigen vaccines, antiproliferative agents (AKT inhibitors) and DNA damage repair-directed therapies (poly(ADP-ribose) polymerase (PARP) inhibitors, serine/threonine-protein kinase ATR (ATR) inhibitors and Wee1-like protein kinase (WEE1) inhibitors). BiTE, bispecific T cell engager ; DC, dendritic cell; TCR , T cell receptor.