A Study to Learn About the Effects of Two Study Medicines (Maplirpacept [PF-07901801] And Glofitamab) When Given Together In People With Relapsed Or Refractory Diffuse Large B Cell Lymphoma.

Phase 1b and Phase 2: Frequency of adverse events (AE)

Type and severity (severity according to the National Cancer Institute \[NCI\] Common Terminology Criteria for Adverse Events \[CTCAE\], version 5.0). Severity of Cytokine Release Syndrome (CRS) and Immune effector cell-associated neurotoxicity syndrome (ICANS) assessed according to ASTCT criteria.

Time frame: Time from the date of first dose of study intervention through 28 days after last dose of PF-07901801 or 90 days after last dose of glofitamab or obinutuzumab (assessed up to approximately 24 months)

Phase 1b and Phase 2: Frequency of clinical laboratory abnormalities

Type and severity (severity according to the National Cancer Institute \[NCI\] Common Terminology Criteria for Adverse Events \[CTCAE\], version 5.0).

Time frame: Time from the date of first dose of study intervention through 28 days after last dose of PF-07901801 or 90 days after last dose of glofitamab or obinutuzumab (assessed up to approximately 24 months)

Phase 1b: Objective Response (OR)

OR defined as proportion of participants with objective response based assessment of complete response (CR) or partial response (PR) according to Lugano Response Classification Criteria 2014.

Time frame: Time from the date of first dose of study intervention until the first documentation of disease progression, death, or start of new anticancer therapy (assessed up to approximately 24 months)

Phase 1b and Phase 2: Duration of Response (DoR)

DoR defined as the time from the first documentation of OR until progressive disease (PD), or death due to any cause, whichever occurs first.

Time frame: Time from the date of first dose of study intervention until the first documentation of disease progression, death, or start of new anticancer therapy (assessed up to approximately 24 months)

Phase 1b and Phase 2: Complete Response (CR)

CR defined per Lugano Response Classification Criteria 2014

Time frame: Time from the date of first dose of study intervention until the first documentation of disease progression, death, or start of new anticancer therapy (assessed up to approximately 24 months)

Phase 1b and Phase 2: Duration of Complete Response (DoCR)

DoCR defined as the time from the first documentation of a CR until PD, or death due to any cause, whichever occurs first.

Time frame: Time from the date of first dose of study intervention until PD, or death due to any cause, whichever occurs first (assessed up to approximately 24 months)

Phase 1b and Phase 2: Progression Free Survival (PFS)

PFS is defined as the time from the date of first dose until PD per Lugano Response Classification Criteria 2014, or death due to any cause, whichever occurs first.

Time frame: Time from the date of first dose of study intervention until PD, or death due to any cause, whichever occurs first (assessed up to approximately 24 months)

Phase 1b and Phase 2: Serum Concentration Versus Time Summary of PF-07901801

Pre- and post-dose concentrations of PF-07901801

Time frame: Pre and post-infusion on Day 1 of Cycle 1 and 2 (each cycle is 21 days), Pre-infusion on Day 8 of Cycle 1, Pre-infusion on Day 1 of Cycles 3, 4, 5, 7, 10, 13 and every 6 cycle thereafter until end of treatment (approximately 24 months)

Phase 1b and Phase 2: Number of participants with Anti-Drug Antibody (ADA) against PF-07901801

To evaluate immunogenicity of PF-07901801

Time frame: On the first day of every 21-day cycle through 5 cycles, then every third cycle from cycle 7 through cycle 13 and then every sixth cycle thereafter until end of PF-07901801 treatment (assessed up to approximately 24 months)

Phase 1b and Phase 2: Number of participants with Neutralizing antibody (NAb) for PF-07901801

To evaluate immunogenicity of PF-07901801

Time frame: On the first day of every 21-day cycle through 5 cycles, then every third cycle from cycle 7 through cycle 13 and then every sixth cycle thereafter until end of PF-07901801 treatment (assessed up to approximately 24 months)