CD274 and lung adenocarcinoma: Case Report: pembrolizumab monotherapy achieves durable disease control in a patient with &lt;i&gt;BRAF&lt;/i&gt; V600E-mutant advanced lung adenocarcinoma and high PD-L1 expression intolerant to &lt;i&gt;BRAF&lt;/i&gt;/&lt;i&gt;MEK&lt;/i&gt; inhibition.