Patients must not have received a live attenuated vaccination within 28 days prior to sub-study registration Live vaccination is not allowed for at least 4 weeks prior to the start of AMG 757 treatment, during treatment, and until end of last study dose Vaccination with any live virus vaccine within 4 weeks prior to the initiation of study drug administration. Inactivated annual influenza vaccination is allowed Has received a live vaccine within 30 days prior to the first dose of study drug; seasonal influenza vaccination is permitted excluding the nasal spray formulation Vaccination with any live virus vaccine within 4 weeks prior to the initiation of study drug administration. Inactivated annual influenza vaccination is allowed Vaccination with a live vaccine < 28 days prior to the start of treatment Received live or attenuated vaccination within 28 days prior to the start of NMA-LD Live vaccination within the last 30 days Vaccination with a live vaccine a minimum of 28 days prior to the start of treatment Have received any live vaccination within 28 days of first dose of study drug Vaccination with a live vaccine a minimum of 28 days prior to the start of treatment Vaccination with live vaccines within 28 days prior to the start of Cycle 1 Vaccination with a live vaccine within 28 days of the initiation of treatment Live attenuated vaccination administered within 30 days prior to randomization. Vaccination with live vaccines within 28 days prior to start of treatment have received any recent (within 28 days prior to randomization) live virus vaccination Vaccination within 2 weeks of enrollment (except for annual flu vaccine). Patients must not have received immunization with an attenuated live vaccine within seven days prior to registration nor have plans to receive such vaccination while on protocol treatment Patients must not have received a live attenuated vaccination within 28 days prior to sub-study registration Patients must not have received a live attenuated vaccination within 28 days prior to RE-TREATMENT registration Vaccination with a live vaccine within 28 days prior to treatment Vaccination with a live virus vaccine within 28 days prior to Day 1 of Cycle 1 Participants in Phase 1b Stage Only: Vaccination with live vaccines within 6 months before Cycle 1, Day 1 Vaccination with live vaccines within 28 days prior to randomization Live-virus vaccination within 30 days prior to day 1 of protocol therapy Vaccination with a live virus vaccine or live attenuated vaccine within 28 days prior to D1C1 Vaccination with a live vaccine a minimum of 28 days prior to the start of treatment Vaccination with a live vaccine < 28 days prior to the start of treatment Vaccination with a live vaccine a minimum of 30 days prior to study treatment Vaccination with a live vaccine within 28 days of the initiation of treatment Vaccination with a live vaccine within 28 days prior to randomization Subjects who have received live virus vaccination within the 4 weeks prior to planned initiation of study treatment Vaccination with a live vaccine within 28 days prior to randomization Live vaccination within 4 weeks of the first dose of avelumab Vaccination with a live vaccine a minimum of 28 days prior to randomization Meningococcal vaccine(s) prior to LFG316 treatment if prior vaccination cannot be confirmed. The choice of vaccine(s) should take into account the serotypes prevalent in the geographic areas in which study patients will be enrolled. In case vaccination is not possible or will result in an unfavorable risk benefit ratio as judged by the investigator, vaccination can be postponed until deemed likely to be effective. Patients <18 years old should receive vaccination for the prevention of S. pneumoniae and H. influenzae type b prior to LFG316 administration. In case vaccination is not possible or will result in an unfavorable risk benefit ratio as judged by the investigator, vaccination can be postponed until deemed likely to be effective. Vaccination with a live vaccine a minimum of 28 days prior to the start of treatment Vaccination with a live-virus vaccine up to 4 weeks prior to onset of study treatment. Vaccination with a live vaccine a minimum of 4 weeks prior to study enrollment Patients must not previously have received the Prevnar 13 pneumococcal vaccination; NOTE: previous vaccination with Pneumovax (PCV23) is permitted but must have been at least 365 days prior to registration Vaccination with live vaccines within 28 days prior to treatment Vaccination with a live vaccine a minimum of 28 days prior to the start of Cycle 1 Vaccination with live attenuated vaccine within 28 days prior to day 1 of PROSTVAC-V/F administration or vaccination with a killed vaccine within 14 days prior to day 1 of PROSTVAC-V/F Have received a live vaccination within 30 days of study start.