The objective of this study is to evaluate the safety and efficacy of concurrent administration of influenza vaccine in patients receiving anti-PD1 immunotherapy (nivolumab or pembrolizumab). This will be a prospective observational study, aiming to assess patient tolerance of treatment, adverse events (incidence, grade, need for hospitalization), incidence of influenza infections, and seroconversion rates.

Inclusion Criteria:

• 18 years or older
• Currently receiving immunotherapy with anti-PD-1 agents (Nivolumab or Pembrolizumab)
• Have not received influenza vaccination prior to study entry date for the upcoming flu season 2016-2017
• No previous contraindication to receiving influenza vaccination
• Histologically proven cancer
• Expected lifetime of at least 12 weeks

Exclusion Criteria:

• Previous cancer
• Autoimmune disease or immunosuppressive treatments
• Corticosteroid treatment
• Those who have a potential indication to change chemotherapy treatment in 42 days following start of treatment
• History of clinically or virologically confirmed influenza infection in the previous six months
• Previous contraindication to receiving influenza vaccination
• Previous allergic/adverse reaction with influenza vaccination
• Have received influenza vaccination prior to study entry date for upcoming 2016-2017 flu season
• Positive anti influenza antibody titers as determined by the baseline blood determination (day 0)

Patients 18 years or older or are receiving either nivolumab or pembrolizumab who have no yet received the influenza vaccine.