Immunotherapy Checkpoint Inhibitors: A Clinical Guide for Oncologists

Checkpoint Inhibitor Landscape in 2026

Immune checkpoint inhibitors (ICIs) have become the backbone of treatment for numerous solid tumors. With over 80 FDA-approved indications across pembrolizumab, nivolumab, atezolizumab, durvalumab, and ipilimumab, the clinical landscape has become increasingly complex. This guide provides a practical framework for selecting, monitoring, and managing checkpoint inhibitor therapy.

Biomarker-Driven Patient Selection

PD-L1 expression (measured by TPS or CPS depending on tumor type), microsatellite instability (MSI-H/dMMR), and tumor mutational burden (TMB) remain the primary biomarkers guiding ICI selection. In NSCLC, PD-L1 TPS above 50% predicts robust response to pembrolizumab monotherapy, while patients with TPS 1-49% generally require combination chemoimmunotherapy.

Managing Immune-Related Adverse Events

Immune-related adverse events (irAEs) affect 60-80% of patients receiving ICI therapy, with grade 3-4 events occurring in 10-30%. The most common irAEs include dermatologic toxicity (rash, pruritus), endocrinopathies (thyroiditis, adrenal insufficiency), hepatitis, colitis, and pneumonitis. Early recognition and grading-appropriate management with corticosteroids is essential.