Exhibit 99.5

February 15, 2021

Via Email

Immunocore Holdings plc

92 Park Drive

Milton Park

Abingdon, Oxfordshire

United Kingdom OX14 4RY

Re: Beneficial Ownership Conversion Limitations

Dear Sirs/Madams:

Reference is made to the new Articles of Association of Immunocore Holdings plc (“Immunocore”) adopted by a special resolution effective on 3 February 2021 (the “Articles”), which became effective on 9 February 2021.

Pursuant to Section 2 of the Articles, the term “Beneficial Ownership Limitation” is defined as follows (emphasis added):

Beneficial Ownership Limitation means initially 9.99% of any class of securities of the Company registered under the Exchange Act, which percentage may be increased or decreased on a holder-by-holder basis by a holder of Non Voting Shares to such other percentage as such holder may designate in writing (with any decrease to be effective upon at least sixty one (61) days’ notice) to the Company, provided, however, that: (i) any such increase shall not exceed 19.9% of any class of securities of the Company registered under the Exchange Act; and (ii) any such increase or decrease shall only be applicable to such holder in relation to such securities. For purposes of calculating the Beneficial Ownership Limitation, a holder may rely on the number of outstanding shares of the subject class as stated in the most recent of the following: (A) the Company’s most recent periodic or annual filing; (B) a more recent public announcement by the Company that is publicly filed; or (C) a more recent notice by the Company or the Company’s registrar to the holder setting forth the number of shares then outstanding. Upon the written request of a holder (which may be by email with confirmation), the Company shall, within five (5) Business Days thereof, confirm in writing to such holder (which may be via email) the number of shares then outstanding;

As you are aware, the intent of the Beneficial Ownership Limitation is to avoid under the imputation of beneficial ownership (as determined in accordance with Rule 13d-3 of the Securities and Exchange Commission (“SEC”)) of voting securities to a given shareholder, to the extent that such voting securities cannot be acquired within a given 60-day period. In light of the intent of this term, it has come to our attention that there was a scrivener’s error in the Articles, where the highlighted term “decrease” was, in fact, meant to refer to an “increase” in the beneficial ownership conversion limit which shall not be effective until sixty one (61) days’ following notice of such change to Immunocore.

In light of this error, Baker Brothers Life Sciences, L.P. (“BBLSLP”) and 667, L.P. (“667”) (BBLSLP and 667 being referred to herein as the “BBI Entities”) hereby irrevocably waive any right to increase the Beneficial Ownership Limitation upon less than 61 days’ prior written notice to Immunocore, and acknowledge and agree that Immunocore shall disregard any purported increase in the Beneficial Ownership Limitation that is effected by the BBI Entities with fewer than 61 days’ prior written notice.

Moreover, for the avoidance of doubt, when determining the beneficial ownership of BBLSLP and 667, the parties shall determine beneficial ownership in accordance with Regulation 13D-G, which provides for, among other things, the aggregation of holdings of affiliates and any member of a “group” within the meaning of Section 13(d) of the Securities Exchange Act of 1934.

Please acknowledge this waiver and agree that Immunocore will not accept a designation or other instruction from the BBI Entities that is at variance with the foregoing by signing and returning this letter to us.

[Signatures appear on following page.]