Patient has pleural effusion, ascites, or pericardial fluid requiring drainage Note: Patient who had drain removal ? days prior to planned first dose of study drug and has no sign of worsening is eligible Uncontrolled pleural effusion, pericardial effusion, or ascites requiring repeated drainage more than once every days Uncontrolled pleural effusion, pericardial effusion, or ascites requiring recurrent drainage procedures Uncontrolled tumor-related pain; pleural effusion, pericardial effusion, or ascites requiring recurrent drainage procedures; or, hypercalcemia or symptomatic hypercalcemia requiring continued use of bisphosphonate therapy or denosumab. Uncontrolled pleural effusion, pericardial effusion, or ascites requiring repeated drainage more than once every days Uncontrolled pleural effusion, pericardial effusion, or ascites requiring recurrent drainage procedures (once monthly or more frequently) (patients with indwelling catheters such as PleurX are allowed) Uncontrolled pleural effusion, pericardial effusion, or ascites requiring recurrent drainage procedures (once monthly or more frequently) Ascites, pleural effusion, or pericardial fluid requiring drainage in the last weeks prior to registration Grade or higher ascites, pleural, or pericardial effusion within weeks of study enrollment or any history of recurrent grade or higher effusions requiring ongoing drainage. Uncontrolled pleural or pericardial effusion or ascites that would require recurrent drainage Uncontrolled pleural effusion, pericardial effusion, or ascites requiring recurrent drainage procedures (once monthly or more frequently)\r\n* Subjects with indwelling drainage catheters are allowed Patients with large and recurrent pleural or peritoneal effusions requiring frequent drainage (e.g. weekly); patients with any amount of clinically significant pericardial effusion Uncontrolled pleural or pericardial effusion or ascites that would require recurrent drainage Uncontrollable pleural effusion, pericardial effusion, or ascites requiring frequent drainage Uncontrolled pleural effusion, pericardial effusion, or ascites requiring recurrent drainage procedures >/= time per month Patients with large and recurrent pleural or peritoneal effusions requiring frequent drainage (e.g. weekly); patients with any amount of clinically significant pericardial effusion Has significant ascites or pleural effusion requiring drainage for symptom relief Uncontrolled effusion, pericardial effusion, or ascites requiring recurrent drainage procedures (once monthly or more frequently) Ascites, pleural effusion or pericardial fluid requiring drainage in the last weeks Patients with large and recurrent pleural or peritoneal effusions requiring frequent drainage (e.g. weekly); patients with any amount of clinically significant pericardial effusion Uncontrolled pleural effusion, pericardial effusion, or ascites requiring drainage at least once monthly. Uncontrolled pleural effusion, pericardial effusion, or ascites requiring recurrent drainage procedures (once monthly or more frequently); participants with indwelling catheters are eligible Subjects with ascites or pleural effusion requiring drainage within the last days. Uncontrolled pleural, pericardial effusions, or ascites requiring recurrent drainage procedures Uncontrolled pleural effusion, pericardial effusion, or ascites (indwelling drainage catheters allowed) Uncontrolled pleural effusion, pericardial effusion, or ascites requiring recurrent drainage procedures (once monthly or more frequently) Uncontrolled tumor-related pain or uncontrolled pleural effusion, pericardial effusion, or ascites requiring recurrent (once monthly or more frequently) drainage procedures Uncontrolled pleural effusion, pericardial effusion, or ascites requiring recurrent drainage procedures Patients with a pleural effusion requiring continuous drainage Symptomatic pleural effusion (> CTCAE Grade dyspnea) that is not amenable to drainage Patients require regular ascites/pleural effusion drainage Patient with pleural effusion, ascites, or pericardial fluid requiring drainage. Patient has pleural effusion, ascites, or pericardial fluid requiring drainage. Note: Patient who had drain removal ? days prior to planned first dose of study drug and has no sign of worsening is eligible. Pleural effusion requiring repetitive drainage, i.e., an indwelling catheter or thoracenteses with weeks of the first dose of mogamulizumab; Pleural effusion, pericardial fluid, or ascites requiring drainage every other week or more frequently Uncontrolled pleural effusion, pericardial effusion, or ascites requiring recurrent drainage procedures Uncontrolled pleural effusion, pericardial effusion, or ascites requiring recurrent drainage procedures No effusion or ascites > L prior to drainage Uncontrolled pleural effusion, pericardial effusion or ascites requiring recurrent drainage procedures Uncontrolled pleural effusion, pericardial effusion, or ascites requiring recurrent drainage procedures (once monthly or more frequently)