Copy number alterations (CNAs) to chromosome 9p24.1 (i.e., polysomy, copy gain, amplification, rarely translocation), leading to increased expression of PD-1 ligands in cHL, PMBCL and some extranodal large B-cell NHLs, are an important mechanism of tumor immune evasion. The gene discussed is PDCD1; the disease is neoplasm.